Auto Air Conditioning & Heater Repair: air conditioning, buick rendezvous, tina tina

Question
I have a 2006 Buick Rendezvous and on the way home from a vacation our Air Conditioner was working fine then all of the sudden it got warm and then hot...air blowing just only hot!  I have been told that it might be a fuse.  I looked under the hood and found the fuse marked Air Conditioning Compressor Clutch and it looked fine so, I pulled the Air Conditioning Clutch Relay and it looked slightly yellow brownish on the outside of the gray cover.  Could this be my problem?  The fuses were the ones under the hood.  I also noticed that the inside fuse box had some HVAC Mode and Temp Motors and Head Up display but, it was getting dark and I could not check this one tonight.  Could a fuse make your air blow hot or is it probably something else all together?

Thanks, Tina

Answer
Tina,
Heck of a way to end a vacation. Hope the rest of the trip was good enough to make up for it. :)
First, just because the fuse looked fine, is not always a good indicator. You really should do a resistance check across it just to make sure. But before we do that....
The discoloring on the relay could very well be an indicator that the relay has burnt up and needs replaced. If it does not look like it was naturally that color, then chances are the coil burnt out of it and caused that discoloration on the side.
But yes, either of these items could stop your AC from working. If you lose power to your compressor clutch, it will disengage and your compressor will not operate. The compressor is much like the heart in the human body, it is what pumps the refrigerant throughout the system making everything else work. If it stops, well... we know where I am going with this.
The first check I want you to make is your low pressure switch. Typically this is located on your accumulator (a silver canister about the girth of a soda can with two hard lines coming out of it)
Disconnect the wiring harness from this plug. Turn your key to the run position, and your A.C. on. With an insulated wire, jump the two connectors in the harness plug to each other. Did you hear your clutch engage? (Should hear a "snap" from your compressor) If you did, let me know, we will explore another possibility. But I am guessing you didn't. If you didn't, and with the information you gave me... fuse looked good, relay had discoloring on it... I am willing to bet that your relay is burnt. Replace it and you should be cruising cool again.
As I stated if you need more assistance, please let me know, and I will be happy to do what I can. Thanks for the question and good luck.