Hot air blowing only from passenger vent issue

[2007GTI]

So this issue has been going on for years, if you put the heat on, it only comes out of the far side passenger face height vent. It gets a little bit hot on other vents, but will not blow out hot air, even if redirected.

Last year I replaced one of the temp flat motors and also the additional water pump which cleared the error, but I still only have hot air coming out of the far passenger vent.  It’s been bugging me so I finally got my trusted mechanic to pull the dash apart, thinking it might be another flap actuator.

After pulling the dash out and flushing the system, he tells me:

I can’t find anything obvious, all flaps and motor working how they should. No fault codes in the climate control module. I’ve flushed the matrix and hasn’t made any difference either.

So anyone got any ideas?

[smig]

Had exactly the same on my Audi A3 (8V). Heater matrix required replacing. Do you have the Silica bag in your coolant expansion tank, is it intact?

[2007GTI]

Coolant Bottle was replaced under warranty when 3 years old, just after I bought it, as it used coolant. They probably did water pump etc, but I was never made aware, the problem was fixed. This was 8 years ago.

1 year ago I took the bag out and it was not damaged.

I read reports from folk online with same issue and they said that they had the matrix replaced and was no different. Also both pipes going in and out of matrix are burning hot, makes no sense!

[SteveAWOL]

Having a similar issue with my GTI whereby the passenger side vents can blow out nice hot air but all those on driver’s side won’t get any more than tepid.

Tried doing the A/C reset trick but that didn’t make any difference.

Took it to dealership who said that heater matrix needs replacing but that wouldn’t be covered by the All-In extended warranty; unlike the thermostat housing which got replaced a few years ago when there was a coolant leak and they removed the dreaded silica bag.