Auto Air Conditioning & Heater Repair: Air conditioner blows hot air only, jumper wire, air conditioner blows hot air

Question
I had my Toyota serviced 2 years ago and they put the new required adapter on my 92 Toyota air conditioner to comply with CA requirements.  After they did the work if I tried to use the air conditioner it would blow the fuse.  I took it back and they said it is an electrical problem, not the air conditioner....where should I start investigating?!

Answer
Gail,
If it is the A/C clutch fuse that is blowing, there are only a few things that would cause a draw on your system large enough to blow your fuse. The first and most obvious is your compressor clutch itself. If it has gone bad, it would continue to try and draw enough energy to energize it until your fuse blows. Another possibility is your A/C clutch relay having gone bad. And a third possibility is that you have a short in the wiring itself. If this adapter you are speaking of is the service port for the conversion to R134A then I do not see this being the service center's fault. If they also installed a high pressure cut-out switch as they are required to do by law under section 609 of the Federal Clean Air Act with a conversion to R134a, then it could be possible they messed something up in the wiring when they installed it. But, verify they did install on. Some shops are on the shady side and don't always do what they are suposed to. Not saying that they did. Just a fact of the matter.

I would recommend that you take this to a reputable A/C shop to have it troubleshot. Unfortunately for me to go through all of the possible checks it would take me hours to type it all out. Confusing you and I both. But, here is a quick check.
With your engine OFF...
An easy check for the clutch is to disconnect the wiring harness from the compressor. Ensure that your compressor has a good ground. With a jumper wire connected directly to the battery, and using a fuse of the same rating in line with the wire, touch it to the compressor hot wire. Did it blow the fuse, or did it engage the clutch? If it blew the fuse, problem found. If it engage the clutch then it is in the relay or a short in the wiring itself.
I hope I was able to help a bit, if I can help you with anything in the future do not hesitate to ask. Thank you for the question and good luck.