MK7 Climatronic upgrade with instructions and pictures.

[2018gti]

@Belthasar I can give you my experience if it helps. I’m not sure about the sunlight sensor because my car came with it. But for the AC run-in, I could only get it to happen in OBDeleven, not by pressing the buttons on the panel. I think I did the Manual start, and my long coding has magnetic clutch as active (there is definitely an ac clutch on my car). But there was another piece to the puzzle which is the “Blower voltage for production routines” adaptation. You should check whether your new panel’s value for this is different from the old one. This seems to control the fan speed during the run in. I kept getting a “evaporator ice up danger” result in the live data until I figured this out - needed to be 9 volts instead of 6. I still don’t know if it was really necessary or if it affects anything else but it helped for me.

In general I would say go through each adaptation in the climate panel and compare to your old. I would disable auxiliary_heating in the 5F module and do the same for Parking heater and Auxiliary heater in the climate coding (unless you have one). The Settings button follows whatever is set in the climate coding so if automatic recirculating and parking heater is disabled, it won’t show up.

 

[Belthasar]

@Belthasar I can give you my experience if it helps. I’m not sure about the sunlight sensor because my car came with it. But for the AC run-in, I could only get it to happen in OBDeleven, not by pressing the buttons on the panel. I think I did the Manual start, and my long coding has magnetic clutch as active (there is definitely an ac clutch on my car). But there was another piece to the puzzle which is the “Blower voltage for production routines” adaptation. You should check whether your new panel’s value for this is different from the old one. This seems to control the fan speed during the run in. I kept getting a “evaporator ice up danger” result in the live data until I figured this out - needed to be 9 volts instead of 6. I still don’t know if it was really necessary or if it affects anything else but it helped for me.

In general I would say go through each adaptation in the climate panel and compare to your old. I would disable auxiliary_heating in the 5F module and do the same for Parking heater and Auxiliary heater in the climate coding (unless you have one). The Settings button follows whatever is set in the climate coding so if automatic recirculating and parking heater is disabled, it won’t show up.

Thanks for sharing your experience!

I'm surprised to read that your car came with the sunlight photo sensor. Are you sure about that? This sensor is different than the sensor used for automatic headlights - any chance you're conflating the two? I thought that the sunlight photo sensor is only installed on cars that left the factory equipped with climatronic. I, too, thought that I had the sensor since the "blank" in the center of the defrost vent looks identical to the sunlight photo sensor.

As for the magnetic clutch, I did some more digging since I made my last post and while I cannot find any definitive answer, I'm seeing evidence to suggest that the NAR model 1.8/2.0 gen 3 EA888 engines do not have a compressor with a magnetic clutch. I thought it was odd that it seemed like my compressor was always spinning, even when A/C is not engaged and it appears that this is the characteristic of a variable displacement compressor (which we definitely have, from what I read). In some of the literature on variable displacement compressors, I'm reading phrases like "Unlike traditional compressors with an electromagnetic compressor, variable displacement compressors..." etc. My climatronic panel (which came from a LHD European country) did not have the magnetic clutch option in long coding as affirmative. Is it possible that your climatronic panel has it enabled, but your car doesn't actually have a clutch? So, I guess this is a question for the mind hive here: Is it possible that some European model mk7 Golfs have different compressors with traditional magnetic clutches, only on engines not available in the NAR market?

Your information about "blower voltage for production routines" is fascinating, and this is the first I'm reading about it. If I get time, I'll have to pull apart the unit again and plug in my old one and see what the value not he old panel is. To your point, I probably should have peeked at its adaptation settings before taking it off so that I could transfer all of the pertinent information to the new one, as the old one is certainly coded to my vehicle's as-built configuration.

 

[Goodbar]

@Goodbar , can you comment on why you jumped the wires from pins 3 and 4?. Was it to simply eliminate one of the sunlight photo sensor error codes (e.g. "missing right sensor signal" or something along those lines?) Wouldn't it "trick" climatronic into thinking that equal sunlight is entering the car on both sides? I ordered another vent temp sensor and plan to wire it up in the passenger side and connect it to pin 14, so am I right in assuming that I can just connect pins 3 and 4 to the intended locations (pins 3 and 1) on J255 if both sensors are present and wired up?

Perhaps more significantly, can you explain how you connected G107's signal ground to J255's pin 17? Did you just use a wire tap? Or did you solder them together. It seems like in the OEM setup, all of these sensors (left vent, right vent, sunlight photo, etc.) share signal ground but do not all "meet up" at J255.

Impressive write-up!

I jumped pins 3 & 4 to get an average of right and left readings from the sun sensor. With this retrofit, we're only using one side of Climatronic. My thinking was to get the same response when the sun is shining on either side of the car. I confirmed that it gives the expected output on the bench before wiring that way for installation. Maybe this doesn't do anything, but it shouldn't cause a problem, either.

I used a PosiTap for the signal ground because I dislike T taps and didn't want to cut the vehicle harness.

 

[2018gti]

I'm surprised to read that your car came with the sunlight photo sensor

I probably should have clarified I have climatronic from factory, which is why I have the sunlight sensor already. I got all this climate panel experience/frustration from retrofitting the Webasto parking heater where I had to swap panels.

I'm seeing evidence to suggest that the NAR model 1.8/2.0 gen 3 EA888 engines do not have a compressor with a magnetic clutch

Yup I have read there can be variations in which AC compressor gets put into cars. I’m like 99% sure mine has a clutch, because with AC off I see the belt turning only the outside of the pulley and the center stays still. It’s definitely possible yours is different though.

If I get time, I'll have to pull apart the unit again and plug in my old one and see what the value not he old panel is

Definitely. That adaptation may not be your issue at all but it’s probably worth a check. I’m also not sure why your fan speed is halfway off the screen lol. Maybe try force restarting the MIB unit? (Holding down the volume knob)

 

[Belthasar]

Impressive write-up!

I jumped pins 3 & 4 to get an average of right and left readings from the sun sensor. With this retrofit, we're only using one side of Climatronic. My thinking was to get the same response when the sun is shining on either side of the car. I confirmed that it gives the expected output on the bench before wiring that way for installation. Maybe this doesn't do anything, but it shouldn't cause a problem, either.

I used a PosiTap for the signal ground because I dislike T taps and didn't want to cut the vehicle harness.

Thanks!

Your rationale for jumping pins 3 and 4 is sensible. I went ahead and ordered another vent sensor - they're cheap enough on Aliexpress, so I plan to just wire it up to pin 14 and add the ground to the pin 17 wire. That means I will be tapping two wires into the one going into pin 17.

Thanks for the PosiTap tip - I've never used one of those so I just watched a video and they seem quite ingenious. What size PosiTap did you use? I guess a more direct question is this: What gauge are the signal wires to J255? I guessed 22awg, but I compared them to a spool of 22 I have on hand and they seem a bit thinner. Maybe 24awg? Also, since I would be tapping into my existing left sensor ground wire (currently connected to pin 17) and connecting the ground wiresfor the right sensor and the sunlight photo sensor, would I need to use two PosiTaps, or does the "Accessory" side of the PosiTap allow for multiple wires?

I probably should have clarified I have climatronic from factory, which is why I have the sunlight sensor already. I got all this climate panel experience/frustration from retrofitting the Webasto parking heater where I had to swap panels.


Yup I have read there can be variations in which AC compressor gets put into cars. I’m like 99% sure mine has a clutch, because with AC off I see the belt turning only the outside of the pulley and the center stays still. It’s definitely possible yours is different though.


Definitely. That adaptation may not be your issue at all but it’s probably worth a check. I’m also not sure why your fan speed is halfway off the screen lol. Maybe try force restarting the MIB unit? (Holding down the volume knob)

Ah! That makes much more sense now. Thanks for clarifying.

Based on what I was reading on some of the forums, I'm surprised to hear that you have a compressor clutch. It seems like VW migrated toward variable displacement compressors around the time the mk5 golf came around, which led me to believe that clutched compressors are fully phased out in the VW lineup now. Either way, I haven't seen the center of my compressor ever sit still, so I'm confident that this is a clutchless style on my engine.

I did end up hooking up my old manual climate panel and doing a complete adaptation scan through VCDS, in addition to taking snapshots of all fifteen bytes in its long coding. Thanks for the suggestion. I did the same for my new climatronic panel, in its current state, which does reflect a few benign tweaks I made prior to doing this that I should have written down. Here's a list of all of my current adaptations in the climatronic unit, with italics denoting adaptation values that are different from their counterparts in the manual unit, and boldface denoting ones that do not exist in the manual unit:

IDE00001-Production mode,Deactivating ,3
IDE01067-Retention of driver's seat heater level,active for 10 minutes ,1
IDE01478-Ignore compressor switch-off by Engine Control Module,Do not ignore ,1
IDE01479-Gear ratio of engine - A/C compressor,0.00 ,1
IDE01483-Blower voltage with voice control,not activated ,1
IDE01488-Auxiliary heating retrofit without CAN,not installed ,1
IDE01493-Sensitivity of air quality sensor,Maximum ,1
IDE01503-Running time of basic setting for compressor break-in,60 s,1
IDE01536-Post heating of auxiliary heating,0 min,1
IDE02155-Reset all counters,not activated ,1
IDE02332-Deactivate production mode,0 ,3
IDE03176-Duration of compressor run in,60 s,1
IDE03251-Stop enable for Start/Stop function,According to function requirements ,1
IDE04159-Deactivation of start/stop function,not active ,1
IDE06425-Dynamometer mode: functional,not active ,1
IDE06544-Speed shut-off threshold for compressor break-in (engine speed),1500 /min,1
IDE06545-Blower voltage for production routines,6.0 V,1
IDE06546-Interior specified temperature for production routines,22 °C,1
IDE06547-Air distribution for production routines,No effect ,1
IDE06593-Air recirculation for production routines,No effect ,1
IDE07108-A/C styles,not activated ,1
IDE07160-MAS01155-Control module switch-off: switch-off time-Control module,20 min,2
IDE07160-MAS05583-Control module switch-off: switch-off time-Data bus,30 min,2
IDE07398-Blower logic with manual adjustment,Matching coding ,1
IDE07585-Hand heater function during cold start,active ,1
IDE07865-Automatic activation of front windshield defroster at MAX-Defrost,not active ,1
IDE07948-Retention of frt.pass. seat heater level,not active ,1
IDE80006-Analysis 6,not activated ,1
IDE80007-Analysis 7,00000000 00000000 ,2
IDE80008-Analysis 8,active ,1
MAS05739-CO2 compressor on-time reduction,Matching coding ,1
MAS06564-Window condensation exterior reduction at high humidity,Matching coding ,1
MAS07251-Cut-in behavior,Matching coding ,1
ENG122844-ENG101574-dimming_characteristic_1-X1,0 ,12
ENG122844-ENG99557-dimming_characteristic_1-X2,6 ,12
ENG122844-ENG102140-dimming_characteristic_1-X3,40 ,12
ENG122844-ENG102936-dimming_characteristic_1-X4,60 ,12
ENG122844-ENG103548-dimming_characteristic_1-X5,80 ,12
ENG122844-ENG113992-dimming_characteristic_1-X6,100 ,12
ENG122844-ENG99777-dimming_characteristic_1-Y1,0 %,12
ENG122844-ENG100480-dimming_characteristic_1-Y2,6 %,12
ENG122844-ENG100773-dimming_characteristic_1-Y3,40 %,12
ENG122844-ENG100631-dimming_characteristic_1-Y4,60 %,12
ENG122844-ENG102174-dimming_characteristic_1-Y5,80 %,12
ENG122844-ENG113993-dimming_characteristic_1-Y6,100 %,12
ENG122845-ENG101574-dimming_characteristic_2-X1,0 ,12
ENG122845-ENG99557-dimming_characteristic_2-X2,10 ,12
ENG122845-ENG102140-dimming_characteristic_2-X3,50 ,12
ENG122845-ENG102936-dimming_characteristic_2-X4,100 ,12
ENG122845-ENG103548-dimming_characteristic_2-X5,220 ,12
ENG122845-ENG113992-dimming_characteristic_2-X6,253 ,12
ENG122845-ENG99777-dimming_characteristic_2-Y1,2 %,12
ENG122845-ENG100480-dimming_characteristic_2-Y2,2 %,12
ENG122845-ENG100773-dimming_characteristic_2-Y3,10 %,12
ENG122845-ENG100631-dimming_characteristic_2-Y4,21 %,12
ENG122845-ENG102174-dimming_characteristic_2-Y5,85 %,12
ENG122845-ENG113993-dimming_characteristic_2-Y6,100 %,12
ENG122846-ENG101574-dimming_characteristic_3-X1,0 ,12
ENG122846-ENG99557-dimming_characteristic_3-X2,10 ,12
ENG122846-ENG102140-dimming_characteristic_3-X3,50 ,12
ENG122846-ENG102936-dimming_characteristic_3-X4,100 ,12
ENG122846-ENG103548-dimming_characteristic_3-X5,220 ,12
ENG122846-ENG113992-dimming_characteristic_3-X6,253 ,12
ENG122846-ENG99777-dimming_characteristic_3-Y1,3 %,12
ENG122846-ENG100480-dimming_characteristic_3-Y2,3 %,12
ENG122846-ENG100773-dimming_characteristic_3-Y3,6 %,12
ENG122846-ENG100631-dimming_characteristic_3-Y4,12 %,12
ENG122846-ENG102174-dimming_characteristic_3-Y5,100 %,12
ENG122846-ENG113993-dimming_characteristic_3-Y6,100 %,12
ENG122847-ENG101574-dimming_characteristic_4-X1,0 ,12
ENG122847-ENG99557-dimming_characteristic_4-X2,10 ,12
ENG122847-ENG102140-dimming_characteristic_4-X3,50 ,12
ENG122847-ENG102936-dimming_characteristic_4-X4,100 ,12
ENG122847-ENG103548-dimming_characteristic_4-X5,220 ,12
ENG122847-ENG113992-dimming_characteristic_4-X6,253 ,12
ENG122847-ENG99777-dimming_characteristic_4-Y1,2 %,12
ENG122847-ENG100480-dimming_characteristic_4-Y2,2 %,12
ENG122847-ENG100773-dimming_characteristic_4-Y3,5 %,12
ENG122847-ENG100631-dimming_characteristic_4-Y4,10 %,12
ENG122847-ENG102174-dimming_characteristic_4-Y5,85 %,12
ENG122847-ENG113993-dimming_characteristic_4-Y6,100 %,12
ENG122848-ENG101574-dimming_characteristic_5-X1,0 ,12
ENG122848-ENG99557-dimming_characteristic_5-X2,10 ,12
ENG122848-ENG102140-dimming_characteristic_5-X3,50 ,12
ENG122848-ENG102936-dimming_characteristic_5-X4,100 ,12
ENG122848-ENG103548-dimming_characteristic_5-X5,220 ,12
ENG122848-ENG113992-dimming_characteristic_5-X6,253 ,12
ENG122848-ENG99777-dimming_characteristic_5-Y1,2 %,12
ENG122848-ENG100480-dimming_characteristic_5-Y2,2 %,12
ENG122848-ENG100773-dimming_characteristic_5-Y3,5 %,12
ENG122848-ENG100631-dimming_characteristic_5-Y4,10 %,12
ENG122848-ENG102174-dimming_characteristic_5-Y5,85 %,12
ENG122848-ENG113993-dimming_characteristic_5-Y6,100 %,12
ENG130577-Knockout_timer_activation,not activated ,1

A couple of comments come to mind. First, blower voltage during production routines is indeed set to 6v, but it was also set to 6v on my old panel. I would never guess that this is supposed to be 9. @2018gti , what led you to believe that 9 is the proper value?

Second, compressor run-in and break-in values are set to 60 seconds, as opposed to the 120 seconds listed in my manual unit. All of the instructions I've seen regarding the run-in routine via OBDEleven and VCDS seem to reference 120 seconds, so this might be a worthwhile change to make en route to getting the VCDS compressor run-in routine to work.

Third I have no idea what Analysis 6 or Analysis 8 are, but 6 does not exist in the manual unit, and 8 was set to not active on the manual unit.

Fourth, I'm a bit fuzzy about what A/C styles means, but in the long coding, this is byte 7 bit 0-3, and is currently set as "readout". I *think* this is the one I changed prior to the above scan in order to enable the climate profiles in the infotainment's climate screen.

It's also worth noting that early on in this process, I watched some live data values at idle related to the compressor and kept on seeing "compressor speed" of 0 when engaging the A/C button. However, after fiddling a bit (and doing the button 17 + 8 combo I described above, but didn't experience the same confirmation that others experienced), I noticed that compressor speed is now showing up at 900/min at idle when I have the a/c button on, and other data values confirm that it's engaged. This is evidence that the "press these buttons together" run-in procedure did something, but I still don't know enough about this to confirm that the procedure was a full success.

Regarding the infotainment readout: I'd love to figure out not only why my fan icon is misaligned (I have reset it a few times to no avail), but also why some of the other touch buttons (e.g. defrost, setup) are missing, and also why climate doesn't appear under the menu when I hit the "car" button on the infotainment unit. Would someone, who has a fully functioning infotainment climate screen, be willing to post a full adaptation scan of module 5F (infotainment) for me to compare?

 

[Cuzoe]

I am quite in love with the amount of detail... you all are folks after my own heart, haha. And now I expect I'll be asking yall questions when I finally get around to doing this. I bought two Ali-express harness/temp sensor sets. My intention is to install both vent sensors (G150/G151) along with foot temp and sun sensor.

@Belthasar I also wondered about the left/right for the sun sensor. I don't know how the sensor works in that regard but your theory is a sound one. Assuming it reports some real-time measuring values someone could see what that output looks like in VCDS/OBDEleven/ODIS.

Regarding your question about grounds... you are correct that they all are common and also correct that it's unlikely they "meet" at J255. In the VW diagram you'll se (244) which is "Sensor ground connection (in climatronic harness)." In reality, there isn't even a central (244) location. It just indicates they are all connected. Ultimately it doesn't make sense to bring all the wires back to one point for a splice, although you could do it that way. What makes more sense (read, cheaper) is that you tie into ground nearest where you need it. This logic doesn't hold for power/signal carrying wire, obviously.

I will not be of much/any use regarding the infotainment screen weirdness. My car has manual climate controls so this bridge is yet to be crossed. My recommendation though... go to the clean scan section on Ross Tech forums and find a car with climatronic. When possible I like to compare to a "from factory" scan as a starting point. Not to say I'm always a fan of what VW chose/chose-not to do given there are so many cool tweaks. But if you get it working cleanly first then you can tweak/revert to your liking. I've wasted many an hour chasing a problem that was caused by a quirk in someone's scan because I didn't know how it should be in the first place.

Regarding some of the adaptations, my semi-educated guesses for a few of them...
Air Quality sensor... this is for some Asian (and maybe other) market cars that have the "Clean Air" button and corresponding clean air sensor. The climatronic system has an additional filter (among other things I suppose) and can run a cycle that cleans the air in the car. It can also automatically switch to recirculate in the event the outside air becomes too dirty.
Window condensation exterior... this I suspect has to do with whether or not you have the Rain/Light/Humidity/Sensor (mounted to the windshield, rear view mirror area)
Post heating of Aux Heating... this would be a TDI thing, as some TDI's have an aux heater (not the webasto) to get warm air in the cabin. In really cold weather the TDI engine may not get up to temp if you're on the highway so you'll never get really warm air in the cabin. I assume this determines whether routed through the aux heater is also routed through the heater core.

I'm expecting to need some help, or be stuck experimenting for a bit, as I chose to go with the touch climatronic panel, PN 5NA 907 044 AJ.

 

[Belthasar]

Dropping in for a quick update.

Still waiting on delivery of a second vent sensor to use in the passenger side, but in the meantime I went ahead and did some research on the posi-taps. I'm still not sure what gauge signal wires we have, but 24awg is my best guess. I ended up ordering a set of the smallest posi taps - these are listed as EX-100R (red and black color) on their website, and they're the ones sized for 24-26awg tap, 18-24awg accessory. The next size up (EX-110M, red and grey color) is sized for 20-22awg tap and 18-24awg accessory. I suspect that either would be fine in this application, but my test tapping of EX-100R yielded a pretty perfectly-sized hole on a one of the signal wires spare climatronic harness that was attached to my climatronic panel when it arrived:

It also appears that the "accessory" side of the smallest posi tap will happily accept two signal ground wires, so I should be all set here to connect the ground wires from the sunlight photo sensor and the second vent sensor to pin 17 by tapping the first vent sensor's lead.

As for the adaptations/programming, I finally had some free time to play around with some of the differences that I listed in my previous post. Here are some notes to share:

• IDE01493-Sensitivity of air quality sensor: I ended up leaving this alone. It was set to "maximum", but the only other options listed were "up", "Medium", "little", and "minimal." I didn't see any adaptation value consistent with "off"
• IDE01536-Post heating of auxiliary heating: This adaptation takes a value in minutes. It was already set to 0 min, so I left it alone
• IDE07585-Hand heater function during cold start: I was not able to change this; when I tried to select "not active", I got an error message: "Subfunction not supported in active session
• IDE07108-A/C styles: Changing this value (to one of the four options if I remember correct) did nothing, so I changed it to the value I already had.
• IDE01503-Running time of basic setting for compressor break-in and IDE03176-Duration of compressor run in: I changed these both to 120s

So the only thing I really changed were the compressor durations. Interestingly, after all of my fiddling, the compressor stopped working (a/c button light wouldn't even come on), so this was a good time to see if changing the durations would finally allow me to run IDE01938-Compressor run in: manual start and/or IDE02259-Compressor break-in: automatic start. Sadly, I got the same error message as before ("ERROR: Conditions not correct or request sequence error"), so changing the duration was ineffective. The only way I was able to get the compressor to work again was to do the 17 + 8 and 16 + 8 button pressing procedure (and I'm unsure of which of these two made it work again).

That said, @Cuzoe I will be really interested to see how you get the run-in procedure to work on the touch panel if you do not have a button pressing sequence to fall back on. Could you share your climatronic panel adaptations if/when you do get it to work?

Also, good idea to check the ross-tech forums for adaptations in module 5F (infotainment). I wasn't able to find a stock readout over there, though. I'd still love to see someone's adaptation list (and long coding setup) where the car was originally not equipped with climatronic, but after successful retrofit they got the infotainment unit to duplicate all of the factory readouts. It's worth noting that I don't have the stock screen (I upgraded to the 8" matte Euro screen), but my understanding is that this is really just a monitor and shouldn't really have any alternate adaptation setup required.

 

[Belthasar]

I take back what I said earlier about not being able to find an admap for 5F on the ross-tech forums. I was able to locate a dropbox link with a full stock admap for 5F on multiple early mk7 models in different regions. The closest match for me is the 2015 1.8t highline (so I presume it's equipped with climatronic), even though this would be MiB 1. I noticed a subtle difference in his adaptations versus mine:

ENG122227-ENG117488-Car_Function_Adaptations_Gen2-menu_display_ACC_over_threshold_high

His was set to 'activated.' Mine was not. Changing this resulted in the following:

Looks like this adaptation properly aligned the "auto" icon!

I can't, however, figure out how to populate the missing touch buttons. Can someone confirm a list of what I'm missing on this screen? Defrost? Settings?

Also, it is my understanding that the stock infotainment menu screen for climatronic-equipped models has a "climate" menu item that brings you to the above screen, no? I don't have this option in the menu:

Much of this is cosmetic at this point, as these touch buttons offer redundant functionality. However, I would like to figure out how to enable these to make it as factory as possible.

I also have a few questions about climatronic functionality:

When you press "auto" when auto is already engaged, does it do anything?

Specifically, if I press auto when it's already on, nothing happens. In other makes/models, this usually returns the climate control panel to the last combination of manual settings (e.g. fan speed, which vents are open). In order to return to manual control, I have to make a manual change, but sometimes I just want to go back to what it was before I started auto. Is this an adaptation issue, or is this how stock climatronic works?

Are you able to run recirculation while auto is engaged?

If I press the recirc button, the panel switches to manual control. I'm not able to have both auto and recirc enabled at the same time. Is this normal?

When you turn on auto, does the panel also switch on A/C?

This seems strange to me, but it might be a german car thing. Is the assumption that even in a heating scenario, the user is going to want dehumidification? If so, are we missing any sensors in this retrofit that would affect how climatronic handles compressor usage?

Thanks again for all of the great info in this thread.

 

[2018gti]

@Belthasar that's great to see you figured out the weird alignment issue. Here's how my Mk7.5 looks on the climate screen - I think the only thing you're missing is the Sync button. Unfortunately I'm not sure how or why it's not showing up for you.. unless it's something they only added to the facelifts.

About the auto button, mine just stays in Auto no matter how many times it's pushed. And the A/C light always comes on with it too. I basically never push the A/C button to turn It off anymore because I trust the system will figure it out. It keeps track of the evaporator temperature, inside humidity from the rain/light sensor, and I'm sure other sensors to determine how much to run the A/C. I can tell (and see) even when it says A/C "on", if it's dry out, the compressor will not actually be spinning.

And I can confirm for the recirculate too. When I press it the Auto light goes out. You can I believe enable auto recirculation in coding, but I think that is intended to work with an air quality sensor.

 

[Belthasar]

Thanks for posting the comparison, @2018gti. What options show up when you press the "settings" button? I still can't seem to get that button to show up again (and I can't remember for the life of me which adaptation change caused it to disappear). I only remember seeing auto recirculation, and something involving the aux heater in that settings menu, but neither of those should be relevant to the NAR models, which have neither air quality sensors nor aux heaters. I'd be curious to know what's in your settings menu.

Thanks for corroborating the A/C and auto button behaviors. I still wonder: is there a humidity sensor that factory climatronic-equipped cars have to help the compressor usage decisions?

 

[Belthasar]

Update: Sunlight photo sensor is alive!

Today I installed G151 (Passenger vent sensor) and finally wired up G107 (the sunlight photo sensor) to the climatronic panel. The Posi Tap worked like a charm (thanks for the suggestion @Goodbar !). As expected, it was no problem combining two signal ground wires on the accessory side of the smallest Posi Tap.

Please excuse the random soldered/heatshrink-wrapped wire. When connecting the new pins to J255, I accidentally placed the wrong wire in the slot for Pin 1. When removing it, it got stuck and snapped, so I had to dig it out and, in lieu of crimping on a new terminal connector (since I had none available), I opted to just remove the corresponding pin on the cut harness that was included with my used climatronic unit and strip and solder it to the wire with the broken terminal. Should hold up no problem, but lesson learned: some of these pins are difficult to remove and can get stuck. Triple check that you have the right slot before pushing any of them in! Also note that, quite annoyingly, the harness new vent temp sensor I got from aliexpress (different seller than the one I got the first two from) has different color wires than the correctly-colored harness I installed on the driver side. If it helps anyone in the future: when looking at the male end of the two-pin vent temp sensor connector with the notch facing upward, the wire on the right is ground. This was green/black on the one I received (as opposed to green/purple as listed for J255 pin 17 in the wiring diagrams).

I fired up VCDS and was greeted by pleasant info - only 7 error messages in the HVAC module now; all of the errors related to the sunlight photo sensor and right vent temp sensor are gone. It also appears that the sensors are working just fine. I took a video illustrating what happens when you drive into sunlight:

How very cool. The sunlight photo sensor doesn't pick up anything from my garage overhead light, but the second I move the car into sunlight it registers nonzero intensity. It's also worth noting that, in this video, my car was facing west at approximately noon, so the sunlight was coming directly from the left side of the car. The sensor data you see corroborates that. Later on, I turned around the car and the right side intensity registered a higher value, so the car definitely knows where the sun is shining in from.

I'm beginning to wonder whether the left/right values have anything to do with the presence of both vent temperature sensors, or if it's the sunlight photo sensor itself that is capable of detecting the direction the sunlight is coming from. As you can see in the video, both vent temp sensors registered near identical values and the sunlight intensity values displayed immediately. So I'm beginning to wonder if having the second vent sensor is even necessary.

Another thought: I am wondering how a fully-functional factory climatronic unit actually uses the left/right sunlight intensity data. As you can see in the video, I was also logging left temperature and right temperature flap values, expecting the asymmetric sunlight to affect what the car does to the driver and passenger sides. I was actually worried about this, thinking that it would try to enact dual zone temperature capabilities that are absent in this retrofit (in which case jumping the wires from pins 3 and 4 as @Goodbar did would be preferable, no?). However, as you can see in the video, both the left and right temp flaps changed when sunlight was detected, but they both changed by the same amount. I would have expected the left side to have dropped further than the right side since the sunlight photo sensor indicated (correctly) that there was more intense sunlight on the left). Just for the heck of it, I turned on the A/C and dropped the temp to its lowest setting, and still the asymmetric sunlight did not asymmetrically affect these temp flap values. Perhaps when SYNC is enabled, all dual zone functionality ceases? It's worth noting that when I disabled SYNC and set the passenger side to a different temperature, the right side temp flap values changed accordingly (although no actual vent temperature changes occurred, due to the missing motors. I'd be interested in hearing everyone's thoughts on this, and whether someone like @2018gti with factory climatronic can log the same data and see if it behaves the same.

tl;dr I'm not sure that the second vent temp sensor is necessary in order for the sunlight photo sensor to work as intended, but at least it eliminates one of those pesky error codes.

Also, a question for the mind hive: Is it normal for the footwell temperatures to be consistenly higher than the left/right vent temps? Unless I manually change to floor only or vent only, it seems like my footwell is always about 10 degrees (C) warmer than the upper vents.

 

[Cuzoe]

This is awesome... for cars that actually have dual zone (climatronic) and not just half of it like us... knowing where the sun is coming from makes sense if trying to maintain a given temperature. The sensor and the vent temp sensor info, together, should theoretically impact how the system works. Even if temperatures are synced in car with factory climatronic, knowing the sun is on the right side means the air from that vent needs to be a little cooler. Very neat stuff... but moot for cars without actual climatronic.

 

[Belthasar]

This is awesome... for cars that actually have dual zone (climatronic) and not just half of it like us... knowing where the sun is coming from makes sense if trying to maintain a given temperature. The sensor and the vent temp sensor info, together, should theoretically impact how the system works. Even if temperatures are synced in car with factory climatronic, knowing the sun is on the right side means the air from that vent needs to be a little cooler. Very neat stuff... but moot for cars without actual climatronic.

Agreed - this is really cool engineering. I suspect that if I were to pop out the sunlight photo sensor, leave it plugged in, and rotate it 180 degrees, then left and right intensity values would more or less swap. I strongly suspect that the left/right side capabilities are built into the sensor itself and have nothing to do with the vent sensors, but I could be wrong.

 

[Cuzoe]

I think you're right... system needs (does) know where the sun is coming from... the vent sensors are just feedback so the target air temperature can be adjusted. If the sun is on the left side the system's actual target gets adjusted, in an effort to maintain the temp you've set on the screen/control panel.

It certainly seems the system is well designed. How well it works is subjective... with some saying it's useless/annoying and others loving it. Likely a portion of both sides don't know how it actually works. If you love it you don't care how it works. And some might think it sucks because they don't know how it works, haha.

In our non-climatronic cars, assuming we install both vent sensors and the sun sensor, I guess the adjustment to our single zone will be made no matter which side the sun is coming from. I'm good with that.

 

[2018gti]

I'd be curious to know what's in your settings menu

Yeah so all I have in mine is a checkbox for “Automatic supplementary heater”, only because I retrofitted the parking heater (Webasto). For you I would say it’s normal that you don’t see it, I don’t believe any US Golf has it showing from factory.

whether someone like @2018gti with factory climatronic can log the same data and see if it behaves the same.

As a climatronic-haver I can say I haven’t logged any values but I don’t think it’s a coincidence that when it’s a cold morning and the sun comes out during the drive, the air switches to the face vents and the temp seems to go down a bit. Must be an effect of the sun sensor. I’m not sure about the left/right part of it though, that would be interesting to log some data for.