My 2004 g coupe suddenly stopped blowing cold air.Yesterday it was fine blowing ice cold air and today the a/c simply blows hot air. All functions on the control panel are working.Mechanic checked and it is full of freon. He checked the compressor and it seems to be fine when he directly powered it up. He is clue less. Any one has suggestions on what seams to be the issue. Any relays computer module etc? Houston is hot in summer and its is very difficult to drive in heat.

As always any suggestions will be greatly appreciated,

Thanks
A'amir

 

Unfortunately for you this is a complex system with many costly components. Guessing at relays and computer/modules could be expensive. The first thing I recommend is that you get a Service Manual (SM), there are some self diagnostic checks you can do by following the steps. I bought my SM on eBay, it is a CD.

Six month after I bought my used 2003 Coupe, I had some issues with my A/C also. I did a search on www.youtube.com and found what appeared to be my problem. My car had the original car stereo system and little did I know that my stereo amplifier unit would impact my air conditioning control, but it did. I purchased a good working replacement unit on eBay, I replaced it and all has been working well. You need to do a lot of reading on youtube, and see if you can find something that would help you. With this system, the dealer might be your best option. It sucks but this is a tough one, good luck.

One thing I would try that would not cost you anything, would be a system reboot. I would disconnect the vehicle battery wait a while and reconnect it. Maybe the problem will clear its self during the boot up.

 

Turn on the AC and check to see if the center portion of the pulley for the compressor is also turning. The outer portion is always turning whether the compressor is engaged or not. If the center portion is not turning that is your problem, the compressor is not turning. Check the fuses to see if they are good or are blown. If the fuses are good you could be low on refrigerant and the low pressure switch will not allow the compressor to come on.

 

I disconnected the battery and waited 5 minutes to reconnect. Everything is fine now. Thanks to every ones advice.

 

!NICE! Glad to see the advise worked.

 

So my 06 Coupe doing some thing, I've been doing some major paint sanding and prepping for my Front Carbon Fiber Hood Fenders and Bumper and having a Major issue with my Ivory Pearl White Paint just came off with painters tape when doing a minor blemish from a rock chip. After taping off and repairing it like any normal paint and body work and sanding as I was removing the tape it took every bit of the 3 Stage paint down to the factory grey primer. I was planning on wrapping the car and unaware of the paint issue would've been a waste of money.
Back to the A/C since blowing alot of sanding dust debris it plugged up my rain Drain lines in the sunroof were plugged and gave me the Idea and blew out the a/c drain line was also plugged up from having the fresh air vent sucked in dust and ended up in the tube along with replacing my in car cabin filter was plugged as well. So this was my issue and hope it may help you if you haven't got satisfaction. I've had my G since 2006 and in 17yrs I've gotten to know my girl quite well😉