I've been fighting my a/c for a while now. Finally it quit. Everything checks out including pressure switches, relays, clutch ...  I found the a/c 10A fuse blown, replaced it and it immediately blew again. Tried a 20A fuse, Blew!  Jumped the a/c clutch to the battery through an ammeter, Works fine, draws less than 3 Amps. Where do I go from here?

That fuse doesn't power the compressor directly. It supplies power to the control side of the AC and fan relays right next to it.

Pull the fuse box up and look underneath for any chafed or cut wires.

Edited August 7, 201510 yr by Fairtax4me

Thanks for the tip. I pulled the whole thing apart,
inspected every wire and connection and found nothing that raised
suspicion. then I pulled all the relays, reconnected the negative
battery terminal and started the car. The fuse was still good. the
instant I hit a/c it blew even with the relays were still out!. I'm
pulling my hair out. Could a bad controller cause this? I have a
different one coming in any day now.

Separately, I replaced the
relays, pulled the fuse, jumped the compressor to the battery and it
blew cool wonderful a/c through the vents even with the fuse removed.

I'll have to look at a diagram later to see what else that fuse does.

Its possible you have a short in the fuse box itself that is causing the fuse to blow.

 

What year model and engine?

92 legacy wagon AWD 5MT  All stock 2.2 liter Great car otherwise

It would be nice to know what the fuse number of the fuse that is blowing out. I suspect it is used for the AC control system. I don't have an exact service manual for your model year. You should look into getting a factory service manual to help you solve this issue. Ebay is a good place to find copies. One thing you could do that may help you find the problem is use an ohm meter and monitor the resistance of the protected side of the fuse circuit and ground. You will see a very low resistance value. Then start disconnecting suspected areas of trouble. When the shorted path is disconnected the resistance will go up on the meter. 

I had this same issue a few years back.  Leading up to the fuse blowing was a noisy AC compressor when the clutch was engaged and it only was getting worse.  I am thinking the bearings were going bad causing more resistance and more power needed to move the clutch.  I replaced the AC compressor with a used one and it never happened again.  I am now getting close to the same noises again.  This time I am going with a reman compressor.  The compressors in the yard now are 15+ years old.  Another symptom I am having is hot air when I stop the car.  When I am moving it is somewhat cold. Do you have any of these symptoms?

I have a manual for 92 but no wire diagram for the AC system. If you search around here there are some links to sites with factory service manuals for almost every year and model subaru.