Dual zone A/C not cooling on the left side

[Cheezel]

Hi all, my Jetta doesn’t seem to effectively put cold air to the passenger side. Both sides are selected to the same temperature. Is there a baffle system that may not be working under the dash, or is there a separate air con feed to one side that is much harder to fix?

[BirdManFJ]

What happens if you turn off Dual?

[Cheezel]

No improvement. I can turn the left down to LO and it won’t get any colder. After some time, the general airflow with the recirculate on does get cooler on the left, but never as cool as the right.

[DrMat]

I had similar on our Mk7 Golf except drivers side not heating at all. After some detective work by VW they confirmed all flaps and motors were working correctly and traced it back to a partially blocked heater core. They tried flushing it which helped a bit but in the end we had it replaced and all works fine again.

[Andrejm]

I would start from temperature sensor in dash, each side is reading and maybe wrong temperature on one, and can't adjust like on other side. Cheers