MK7 Climatronic upgrade with instructions and pictures.

[Jachas]

Regarding all of the air quality/humidity sensors: are they necessary for full recirc functionality?

Is necessary for automatic recirculation function. Signal from humidity sensor IMO is used (if is available) for more precise AC and AirCare funcionality, but in most cars, only air quality, without humidity sensor is used, so i expect that exterior humidity signal is nothing essential. For manual recirculation, these sensor is not necessary at all

Interior humidity sensor is used for AirCare function.

With sunlight and all temp sensors you have most important sensors for climatonic (funcionality-wise, would be around MK4 climatronic, because One-zone, no automatic recirc, no AirCare funcion)

 

[Belthasar]

Is necessary for automatic recirculation function. Signal from humidity sensor IMO is used (if is available) for more precise AC and AirCare funcionality, but in most cars, only air quality, without humidity sensor is used, so i expect that exterior humidity signal is nothing essential. For manual recirculation, these sensor is not necessary at all

Interior humidity sensor is used for AirCare function.

With sunlight and all temp sensors you have most important sensors for climatonic (funcionality-wise, would be around MK4 climatronic, because One-zone, no automatic recirc, no AirCare funcion)

Thanks for your detailed explanation (and great MK4 functionality analogy) regarding the extra sensors. My wallet laments your dilligence.

I was able to get 4H0907658 (air quality + humidity sensor, eBay), 4B0972883A (pigtail, aliexpress) and 7L0907323 (mounting clip at my local dealer) all for under $20 so I figured it's worth it. I can follow Cuzoe's install of this and figure out where he tapped into it in the engine bay. @Cuzoe, was it the refrigerant pressure sensor you tied this into?

I suppose this leaves me with one more decision to make: what to do about the windshield rain/humidity sensor. This seems to be fairly expensive and I need to decide whether the functionality it adds is worth it. Cuzoe, did you retrofit this too? I seem to remember you mentioning that you had it installed for something else, but not specifically for this project?

 

[Jachas]

I suppose this leaves me with one more decision to make: what to do about the windshield rain/humidity sensor. This seems to be fairly expensive and I need to decide whether the functionality it adds is worth it

IMO it depends if you have Light/Rain sensor. then is just new Light/Rain/Humidity sensor to buy. Then replace old sensor with new + coding and job done.

I was able to get 4H0907658 (air quality + humidity sensor, eBay), 4B0972883A (pigtail, aliexpress) and 7L0907323 (mounting clip at my local dealer) all for under $20 so I figured it's worth it. I can follow Cuzoe's install of this and figure out where he tapped into it in the engine bay. @Cuzoe, was it the refrigerant pressure sensor you tied this into?

On this LIN bus, 3 things can be connected. Air quality sensor, pressure sensor and blower motor (And all 3 goes to climatrionic unit) So you can tap to any part of the wire to these 2 (pressure sensor and blower motor). But because the wires for pressure sensor goes like 5-10cm from air quality sensor location. Make sure that all you connections (from pigtail of the 4B0 connector and in main harness) is watertight

 

[Belthasar]

IMO it depends if you have Light/Rain sensor. then is just new Light/Rain/Humidity sensor to buy. Then replace old sensor with new + coding and job done.

Sadly, I do not have an existing light/rain sensor (GSW S trim 4Motion). So would this be not worth the expense/effort to add?

On this LIN bus, 3 things can be connected. Air quality sensor, pressure sensor and blower motor (And all 3 goes to climatrionic unit) So you can tap to any part of the wire to these 2 (pressure sensor and blower motor). But because the wires for pressure sensor goes like 5-10cm from air quality sensor location. Make sure that all you connections (from pigtail of the 4B0 connector and in main harness) is watertight

I'll have to take a close look under the hood to get a sense of this, but it doesn't sound too difficult.

 

[Jachas]

Sadly, I do not have an existing light/rain sensor (GSW S trim 4Motion). So would this be not worth the expense/effort to add?

Can be done in 2 ways. Neat way is to change windscreen from "only rear view mirror" to "rear view mirror and rain sensor" (and if you live in colder zone, then you can search for heated windscreen and retrofit it too )

Simpler but not so neat is to search for a bracked/holder of the sensor (from a cracked windshield for example, as it only comes with windscreen, maybe guys from windscreen shops could help?) + glass primer + glue for windscreens and mount it on existing windshield


So I would say that there is "a little bit" of hassle

I'll have to take a close look under the hood to get a sense of this, but it doesn't sound too difficult.

Here's video when you can see how to get to the air quality sensor location and how is mounted. And you see the main harness I was talking about

 

[Belthasar]

Can be done in 2 ways. Neat way is to change windscreen from "only rear view mirror" to "rear view mirror and rain sensor" (and if you live in colder zone, then you can search for heated windscreen and retrofit it too )

Simpler but not so neat is to search for a bracked/holder of the sensor (from a cracked windshield for example, as it only comes with windscreen, maybe guys from windscreen shops could help?) + glass primer + glue for windscreens and mount it on existing windshield


So I would say that there is "a little bit" of hassle

Hmm option 1 is definitely off the table, as my windshield is pit-free and I hesitate to break the factory seal unless necessary (plus this would be very, very expensive for just a minor addition to climatronic functionality). Option 2 is more of what I was hoping for. If I can get a hold of the bracket, does it fit underneath the rear view mirror mounting arm?

Also, my understanding is that factory climatronic cars already have a humidity sensor in this location. Auto headlights upgrade this to the light rain and humidity sensor. Since I have no interest in retrofitting automatic lights, does that make it any easier for me if all I need is the humidity sensor? Can it be mounted somewhere else that doesn't rely on finding the bracket in a wrecked car?

 

[Cuzoe]

@Belthasar If you want to get more "bang for your windshield replacement buck" and want to take up the heated windshield deal, I know a guy...
https://golfmk7.com/forums/index.php?threads/cuzoes-2015-golf-tdi-s-journal.373961/post-7997801

 

[Belthasar]

@Belthasar If you want to get more "bang for your windshield replacement buck" and want to take up the heated windshield deal, I know a guy...
https://golfmk7.com/forums/index.php?threads/cuzoes-2015-golf-tdi-s-journal.373961/post-7997801

Dear lord . I am not going down that rabbit hole This silly little climatronic retrofit project is like pulling on a thread that keeps unraveling a shirt and never ends.

So am I right in saying that if I wanted to mount, at a minimum, a humidity sensor in the factory location or near-factory with something like an aliexpress bracket, I'll be pulling the headliner and running wires to the BCM and fuse box? Unless an alternative location would suffice, like the footwell? Do we have a sense of how climatronic uses the humidity data from the windshield-mounted sensor? Is it to just get an overall sense of how humid the cabin is (and thus decide how much to use the A/C compressor)? Or is it a bit more sophisticated in relying on the humidity at the windshield specifically, so that it might control the defrost flap when needed most?

@Cuzoe , I wish you didn't already have the sensor in place from an unrelated retrofit, because I suspect you'd be grappling with the same questions and coming up with brilliant solutions

 

[bobloblawGTI]

If you already have a rain/light sensor, is it just plug-and-play replace the little puck under the rear view/lane assist camera?

 

[Belthasar]

If you already have a rain/light sensor, is it just plug-and-play replace the little puck under the rear view/lane assist camera?

My understanding is that it's far easier to upgrade in this case:

https://www.golfmk7.com/forums/index.php?threads/light-rain-sensor-retrofit.322687/

This thread describes the opposite (humidity-only upgrade to rain-light-humidity), but all of the sensors fit in the same bracket and your wiring should already be there.

 

[Jachas]

If I can get a hold of the bracket, does it fit underneath the rear view mirror mounting arm?

No, bracket is too big for that (and sensor too). And when you have windscreen with non-automatic dimming, non-automatic light control and non-climatronic. Windscreen has only small black dot under the rear view mirror fixing, like this one. you need windscreen like this one

. Since I have no interest in retrofitting automatic lights, does that make it any easier for me if all I need is the humidity sensor?

No. All 3 types (light/rain sensor, light/rain + humidity sensor, humidity sensor) have the same size and mounting location, only quantity of sensors in one "box" differs

Can it be mounted somewhere else that doesn't rely on finding the bracket in a wrecked car?

Not much, as this sensor is monitoring humidity and temperature in upper part of windscreen and uses that information to know the dew point. With that info, climatronic "knows" how much can "use" recirculation for AirCare function, but without a risk of fogging windscreen

 

[Belthasar]

No, bracket is too big for that (and sensor too). And when you have windscreen with non-automatic dimming, non-automatic light control and non-climatronic. Windscreen has only small black dot under the rear view mirror fixing, like this one. you need windscreen like this one

No. All 3 types (light/rain sensor, light/rain + humidity sensor, humidity sensor) have the same size and mounting location, only quantity of sensors in one "box" differs


Not much, as this sensor is monitoring humidity and temperature in upper part of windscreen and uses that information to know the dew point. With that info, climatronic "knows" how much can "use" recirculation for AirCare function, but without a risk of fogging windscreen

So are you saying that in order to really finish this partial retrofit (all functionality except dual-zone), if your car didn't already come with auto lights and/or rain sensing, then you have to replace the entire windshield? No other way around this?

 

[Jachas]

So are you saying that in order to really finish this partial retrofit (all functionality except dual-zone), if your car didn't already come with auto lights and/or rain sensing, then you have to replace the entire windshield?

To do it OE/Neat way? Yes

No other way around this?

Well, as I earlier:

Simpler but not so neat is to search for a bracked/holder of the sensor (from a cracked windshield for example, as it only comes with windscreen, maybe guys from windscreen shops could help?) + glass primer + glue for windscreens and mount it on existing windshield

Is the only way "around". It looks something like this (double side tape is used in this case)

 

[Cuzoe]

So are you saying that in order to really finish this partial retrofit (all functionality except dual-zone), if your car didn't already come with auto lights and/or rain sensing, then you have to replace the entire windshield? No other way around this?

I suppose you don't have to enable the AirCare function. I did not have it enabled when I had not yet installed the air quality sensor. I had air quality sensor coded as "not installed" though so no faults.

I can't recall on the humidity sensor, sense I had it installed already... but if you can code it as "not installed" then you don't have to enable AirCare function either.


Unrelated to the humidity sensor... you can actually install the right temp flap motor, V159 (and associated wiring/connector). Our non-climatronic box does not have this flap internally but it DOES have the mount point for the motor. The "stops" for this are part of the motor housing itself, so the end-stop adaptation runs and passes. The motor is not actually doing anything since there is no flap, but it makes for no faults.
https://golfmk7.com/forums/index.ph...instructions-and-pictures.379148/post-8058806

 

[Belthasar]

Well, as I earlier:

Is the only way "around". It looks something like this (double side tape is used in this case)

Yikes. That looks terrible. What about something like the aliexpress boxes :



Though I'm not sure if the adhesive in a kit like this would stand out as badly as the double-sided tape in the link you provided.

I suppose you don't have to enable the AirCare function. I did not have it enabled when I had not yet installed the air quality sensor. I had air quality sensor coded as "not installed" though so no faults.

I can't recall on the humidity sensor, sense I had it installed already... but if you can code it as "not installed" then you don't have to enable AirCare function either.


Unrelated to the humidity sensor... you can actually install the right temp flap motor, V159 (and associated wiring/connector). Our non-climatronic box does not have this flap internally but it DOES have the mount point for the motor. The "stops" for this are part of the motor housing itself, so the end-stop adaptation runs and passes. The motor is not actually doing anything since there is no flap, but it makes for no faults.
https://golfmk7.com/forums/index.ph...instructions-and-pictures.379148/post-8058806

What would happen if the air quality/humidity combo sensor is installed, but the interior humidity sensor is not? I wouldn't enable aircare in this situation, but would the exterior humidity data be used by climatronic in any meaningful way? I ask because I did order this sensor before realizing that I'd have to tear out my windshield to do the interior part right.

I did see your post about V159 in my many re-reads of this thread. Seems like it would be a superfluous install just to clear an error code, no? I imagine if you have V159 anyway having bought the entire heater box, then it can't hurt to install. But is there any reason to go out of my way to get one beyond clearing the error code?

What a headache this retrofit has been. I should never have gotten involved.