Cabin heating erratic

[Franklin42]

I have a 2019 E-golf that has some problems with the heating and A/C..

Last winter i started having issues with the cabin heater. It seemed to work fine down to about -10c, but colder than that it would suddenly start blowing cold air randomly.

I measured the temp coming from fans at high setting to about 30c after starting car, then it would suddenly drop to 5-10c after a few min. It will continue to blow cold until i hit the recycle air button or restart with the off button. Then it works for a few min, and down to 5-10c again.

Dealership cant find anything wrong.. checked for leaks, gas level is ok etc..

This summer i had the same problem with cooling the car... seemed to just blow hot air from outside for a few min before the AC kicked in.

And now with -18c I'm freezing cold with the car not heating properly... it kinda works with air recirculation on, but everything gets foggy quick.

Any tips on what the issue could be? Malfunctioning sensors? Dealership said they were getting no fault codes.

 

[Eric1976]

Hi Franklin, I have a 2019 , and have exactly, 100% the same problem as you. Currently my success rate is 100% fixing the problem by doing a reset via A sequence of on and restarting the ventilation.
my mechanic doesn’t find any fault code on the ecu, which should be the case if the well documented valve problem would be the cause.
i read somewhere … trying to find back that post, that some people that has had their valve changed, that their mechanic said they had also change one wire that had abnormal wear and was related with the heating system …. Trying to find that info. To me it would make sens that an abnormal voltage level, due to a ground fault, would trigger an event in the hvac controler unit, hence the reason why were able to successfully reset our fault doing a reset with off/on sequence. If I find the info on that wire I will post it here. Have you found anything On your side ?