Well guys, been looking for threads with clear cut info on the A/C. I want to try to charge it first and see if the compressor comes on, but not sure where to start with this whole thing. I do not know if it's been converted to R-134a. Is there an obvious way to know? I will still be searching for info, but if someone has a checklist or a thread they could direct me to, it would be greatly appreciated. I really don't want tot take to a Volvo house and pay ridiculous money to get it done. Thanks!

 

Well, on further inspection, it looks like it is still the old system. The upper fitting is a Schraeder valve, which tells me it is still R12. I am guessing the compressor is probably shot too then, but I don't know yet. I know you can jump the compressor, but I am not sure how to do that.

 

1st get yourself a set of AC gauges. They make fittings to use on R12 or 134A . If you still have schrader valves then plug in the low pressure hose and see what you have without the engine running. Start from there and if you have pressure (find charts on the web) then you will need to see if the compressor is getting 12V. How long has the system not worked. If it has been down for a few years then you'll have a lot of work getting it going. Find out 1st if there is any freon in the system and then we can go through the procedure to get it running again.

 

You can "jumper" the compressor by shorting the pressure switch on the dryer near the schraeder valve--use a paper clip, plug is + and -. If the compressor runs at that point, chances are that the problem is lack of refrigerant due to a leak. You'd need to find the leak, fix it, refill the system. Problem is that R12 costs a fortune and only special licensed places have it. If your compressor is bad, than a new one is needed and then might as well just convert to R134 refrigerant. On the bright side, the 134 is much cheaper... Even if the compressor is good and it turns on, you can still convert the system to 134. You'll need to change the O rings and the compressor oil. Decisions, decisions...
A/C work usually is too challenging for the novice.

 

I am not sure how long it has been down. I just bought the car a month ago, so it could have been down for some time. When I turn on the A/C from inside the car, you can feel what feels like the compressor coming on, but when I look under the hood, I don't see it coming on. Maybe I am looking at the wrong thing? I know you can usually see the clutch engage. Odd....

As far as A/C gauges, I'll have to see if I can pick up some today. can I get these at any generic auto parts store? As always, thanks for your input!

I am going to give this a shot and see if I can at least save myself the $100 "diagnostic" fee. I have founf R12 on ebay with the kits to install it. Apparently if one buys in small amounts, you don't have to do the whole EPA thing and pay an arm and a leg. I completely agree that A/C is usually for the novice. I am a pretty decent backyard wrencher, so I'll try this myself until I can't go any further.

 

Ok, I tried jumping the switch that I found. It is the only one I found that is near the firewall coming off of the dryer. Is this the right one? I jumped the switch with the wires and tried the prongs coming off the dryer, with the A/C running and A/C on, but no dice. Did I do the procedure correctly?

 

on a 91 and 92, 7/9 turbo, the AC compressor is below the alternator, on the left (US drivers) side of the engine.

here's a (filthy!) 91 turbo...



the compressor is the gold-ish pulley you can see under the radiator hose...

 

Ya, sounds like you did it right. If you compressor didn't turn on, it's bad and you need a new one.

 

well, before replacing the compressor, I'd want to verify that +12 came out of the control wire from the dashboard to that first low pressure switch. and, isn't there a second high pressure switch down by the condensor manifold before it gets to the compressor ?