Had a/c, now I don't
 

Took it in to get a charge, turned the a/c knob, and nothing, no power what so ever. Flipped the knob back and forth and the blower kicked on for a sec and just shut down. Checked all the fuses and they were fine. Went ahead and pulled the switch and replaced with a new one since I had one laying around and was hoping that was it but it wasn't. I noticed that when I hooked a light tester up to the hot wire that was connected to the switch that it would come on, but when I turned the ignition on and off, I would lose power again. Pulled the relay out and disconnected it from the wires. I noticed that the red/wht and blk wire that was connected to the relay had power, but no matter what position the key, I never got a light to show the yellow and red wire had power. Don't enough about the electrical or how relays work to see if the relay is the issue. I did order one in hopes that is the issue though. Any ideas? Thanks...

Re-check the fuse #2 (or A/C Fuse on your model) It may appear to be intact but may have shrunk due to heat the system created.

Rotate it compared to other fuses, I bet it is loose and not making contact causing a short in the system.

Here is my write up on the fix: http://forums.pelicanparts.com/porsche-911-technical-forum/613548-fix-3-2-c-2-fuse-finally.html

It may be your issue as well, those old Fuse Blocks just can't tolerate the extreme heat fluctuations the motors generate.

Jim

Thanks DRACO, I am sure that will definitely come in handy one day. Well it turns out that it was the relay after all. It is amazing how much control a relay has over an ENTIRE a/c system. I could not stop thinking about how much I was hoping it was the relay. I went to pick it up the new relay today and was even talking to the guy on what his thoughts were. We even went so far as to taking the old one apart and he mentioned that it did not look like anything was wrong with it. So, all the way home I was thinking that I have purchased another part that was not going to help. I hooked up the new relay and then went and put the light tester on the hot wire (which was not hot prior to the new relay) that was connected to the a/c control switch. I could not believe my eyes that the wire was actually and finally hot. I went ahead and connected all of the switch wires, turned it on, and immediately heard the compressor and all of the fans kicking in. Everything works beautifully now again and I am back to only needing a charge. Amazing that a $23 part was the culprit to the entire a/c system not functioning.

Congrats!

Thank you for posting the resolution.

No problem Bob, the main reason for posting such a detailed resolution was that I had talked to at least 10 people who had a back ground in cars and electronics. At least 7 of them didn't think the relay was the main issue. :confused: I could have gotten away with only spending $23 had I bought the relay before the new $38 OEM switch... Now I have a new switch laying around when and if the old one decides to go out. Also, the Bentley service manual has been one of the best investments since owning the car. It has actually educated me with the wiring and connections of many things.

Amazing what a little time looking at those things can do for a DIY-er. Spending time in this forum can help your knowledge base grow as well. All the best.

Timely tread as my a/c fans just stopped working for me on my way home tonight! Will have to do a little research, but hope for the cost it is the same problem.

Well, my relay held for 31 years and we still could not tell it was bad. The OEM number is 911-615-103-01. You can get it from Pelican, or a generic one at NAPA, CAR Quest, or other import auto stores. Just give them the OEM number and they should be able to look up a replacement.

I had much the same problem in my 82 SC. Everything just quit working one day but everywhere I checked I had 12 volts. Turns out there was some thermal damage to the fuse block that had been going on for a while. The AC fuse socket was toasted but made enough contact for you to read voltage but not enough contact to pass curent. Theory is the bearings in the smuggler box blower wear out causing the motor to draw excess current. I had to put an in line fuse in place of the bad one in the fuse block and so far so good. KW

well these issues normally occur due to bad relays or fuses and in some cases bad connections here and there..