New to this section but now have a mk6! Heater issues!

[kniterider]

Hi, been on here on and off since about 2003, finally able to post in this section as weve had a mk6 gt tdi a few weeks now! . so need to pick some brains.

Has manual A/C Heating, (i say manual  but its all done by motors / switches / flaps and can read the controller on vag com ) , now get in the car in the morning , drive a few miles heater gets hot and blows warm ari as it should , any position , whether A/c is on or not , then get driving for over 30 mins then youll feel the cabin temp drop , so goto turn knob but its already on max, so ive found turning to cold then back to hot sorts this , for about 1-2 mins then it goes back to cold again. Have run vag com and done various output tests etc on the hvac controller and all good no faults etc, is as thought the motor that controls the heater flap keeps going back to cold at certain times so must be somethign triggering it to tell it to do that either a sensor or similar? Any ideas folks as the warranty we got with the car dosnt cover A/C which they will undoubtibly say it is to get out of paying so may aswell sort my self like normal!

thanks for any help in advance! ..... other than the above issue the mk6 has been great so far!

Cheers

Gaz

[joe6]

Not sure which system you have? Some early MK6s had climatic control (not climatronic) - a temperature sensor that read cabin temperature. The hot water from the engine goes full bore through the heat exchanger in this system and the cold air flaps move to allow more or less cold air in to keep the temperature within a range. If this is what you have then could be the sensor faulty?
Later cars had the basic spec.. Easy to tell as the temp setting has no numbers. The fan speed and air vents are user controlled via the heater control knobs. Just guessing that the controller may be faulty in this case or the flaps have become misaligned but have not experienced this myself.