Hi, I'm a newbie to the forum and hope someone can help with a problem on my aging A4 1.8 t-sport. The heater/air-con has sdeveloped a fault, it always blows very hot, even when it's obviously up to temperaturwe and even if I set the temperature to LOwest. I can hear the compressor kick in and I know that's working as the screan de,ists real quick but the car real hot. I'm thinking the control unit is not detecting the temperature, is there a cabin temperature sensor somewhere and can I fix it. The car is 9 years old but otherwise is in cracking condition. Any suggestions (other than buy a new car:-))?

 

Have someone VAG-COM it.

 

Yep, I know I should but the cost would be more than the car is now worth in the UK. You should see the dealer workshop rates- over £100 or $175 per hour.

 

Well it could be many things. The blendoor actuator may be broken, electrical issues, low or no refridgerent due to leak or damage, bad ac compressor and or bad ac system component (evaporator, condensor etc). Those are all possible issues that would cause your concern.

 

don't take it to the dealers, most garages have the diagnostic hardware to check the system and normal cost is approx £35 , it might just need re-gassing or the air mixer flap motor is stuffed "when did you change the pollen filter" all are only possible solutions

 

Thanks for the advice, maybe a bit more info would help:-

I don't think it's the compressor as I can hear it start-up and even with the compressor turned off the heater shouldn't be blowing such high temp air into the cabin, it would normally be blowing in ambient air from outside, especially if i set the temp to LO.

If I set the temp to say 19 deg c it just blows on max fan with very hot air, even when the cabin temperature is well over 20 deg C. So I think it's more likely to be a problem with the heater control than the compressor.

I have had another problem with the control panel for the climate control that has been there for ages, it occaissionally goes out or flashes and can be brought back on by pressing the surrounding plastic. Whilst this is annoying it doesn't pevent the climate control working and the controls sused to still work.

I've owned this car a 1996 A4 1.8T, it's a very tidy car but has 130,000 miles on the clock so I don't want to spend a lot of money on it. It's in the garage today to have 3 of the links on the front multi-link suspension changed and that's costing enough (£300). So any help you guys can give would be appreciated.

BTW I haven't had the pollen filter changed for ages, surely that wouldn't cause this effect, would it?

 

well its not really my area but the blender motor is the same thing as the flap motor and if not working and stuck on hot will be the problem, you ruled out the a/c because the compressor comes on so its gassed up and fuses are ok,

so its the blender motor ill look for data on it but its been covered and a search might be quicker

 

Thanks, it could well be the flap or flap motor (more like), I used to be able to hear a motor pulsing in the dash wsoon after starting engine but that no longer happens (it could have been the flap motor, it was a servo'd type motor noise).
Just got info (from a search on here) about fault codes and will check those when i get the car back (tonight or tomorrow)

 

i had the same problem with my car, even though the ac system turned on and i heard everything running like it should no cold air at all. even on the lowest temperatire setting. i bought "certified-pre-owned", kinda makes me wonder what they certified, 110 point inspection my @$$. stealerships can be such @$$h*le$. after buying the car and them claiming they fixed the problem, took it back after 2 days of driving it because the issue wasnt resolved. long story short, they ended up really fixing it. in the end it turned out to be that my AC compressor had a hole in it. so my advice would be to start there. have them check the condensor and the compressor 1st. that should narrow down the problem area greatly. best of luck with ur audi.

 

Check the two lines that go to the evaporator. They are located on the right side engine compartment (passenger side US). With the A/C on the line near the battery should be the colder.

The hot air could be caused by the control unit or a malfunctioning door.