Just had auto mirrors installed by a local garage that ONLY deals with retrofitting OEM VAG parts.
Before booking a time he quickly scanned my system and concluded that my stock mk7 had the correct module (5 series) in the passenger side and the old module (3 series) in the drivers side.
He told me that this is very common and might be due to the passenger side mirror needs the newer module to perform the "dip in reverse". All higher spec cars like GTI and Highline comes with two 5 series modules but the lower specs don't. And if they do it's often only in the passenger side. Simply cost savings from VW.
He told me to order a 5 series module for my driver side. I asked if I should go for a specific model (a,b,c etc). He told me that in the 100+ power mirrors he had installed he could not see a patern and that he never had encountered a 5 series module that didn't work with power mirrors. The 3 series modules simply miss some pins inside it and those pins exist in all 5 series modules. The only part I had to make sure was to not get a module from a UK car (unless my car was a RHD car)
So I just ordered a 2014 5 series module from an Audi A3 for my 2016 MK7 (can't remember if it was a or b) of eBay.de for $30 and during the install he swapped it for the old one. Everything worked perfectly. Can fold with my key fob or set it to fold otherwise in the menu.
I was debating doing it myself for a long time - but would have hated to run into problems like this. So I struck a deal for power mirrors (with puddle lights) and a lowline reversing camera in the emblem.
The lowline Camera has better picture quality but lack the dynamic lines of the Highline - that nobody actually use. I was able to demo both camera types before choosing. They both have the same build quality and are both placed hidden inside the emblem. But due to the fact that the high version needs to run its picture trough a small computer to add the moving dynamic lines, the picture quality is noticeable worse. It's not horrible, but considering the lowline is cheaper I choose to go with a clearer picture. I already get the dynamic lines from my parking sensors that works nicely together with the camera.
