Hi, folks. I have an issue with my airconditioning. Sometimes it just doesn't blow cold. The blower fan still works. I'm not sure if it's a heat-soak problem, but it seems to fail after I go for a drive, stop, then restart. The intermittancy seems to be getting worse.

One time I reset the electrical plug on the compressor and it came good, but it may have been coincidence.

I downloaded some wiring diagrams, but they don't show the AC system. I searched online and found a relay associated with the system in the engine bay. The online source labelled it as an AC cutout relay for high engine rpm. I couldn't find any other relays. I cleaned the relay pins, but they didn't look so bad. The car is old, but it only has 60,000km on the clock. 

Does compressor control come from an ECU (directly) or is there another relay somewhere? I also went looking for AC gas pressure switches, but didn't have much luck. Where is the receiver/dryer on these cars?

I have my car routinely serviced at a dealer, so I don't get much hands on experience. My next service is in April. I do have an electrical background however. I regularly work on my weekend car and even offer advice to fellow owners.

Thanks for any tips.

Cheers

Ian

 

The drier is located in the bumper just ahead of the front right wheel arch for most engines on the Mk6.  

I think the compressor is controlled by the GEM but not 100% sure.  My gut feeling would be a worn compressor if the cooling fan runs and there's enough gas in the system.

There was also a recent thread here that suggested that the A/C cuts out if the battery gets low, but to be fair, I'm not sure a 2007 model would be that sophisticated...

On 8/5/2023 at 11:00 PM, TomsFocus said:

The drier is located in the bumper just ahead of the front right wheel arch for most engines on the Mk6.  

 

Thanks. There's a lot of stuff in that corner, so I'll have another look. I did order a workshop manual, so hopefully that will give me some more clues regarding control.

 

On 8/6/2023 at 12:33 AM, StephenFord said:

here was also a recent thread here that suggested that the A/C cuts out if the battery gets low, but to be fair, I'm not sure a 2007 model would be that sophisticated...

Thanks. I haven't noticed anything unusual relating to power. Starting is easy. I did recently add a hardwired dashcam which runs 24/7, but the problem started before this.

Well, my manual arrived, but it was quite useless (with regards to wiring). It didn't even have schematics for engine control. The AC system seems to be very basic. No ECU is shown.

Half the AC controls seem to be mechanical, not electric. i.e. air direction and heat. Only the fan speed and compressor ON button seems to be electric, but there must be some intelligence in the system. The AC ON button is momentary (not latching) and the system remembers if the AC was left on after engine shutdown). Weird.