Air Conditioner
 

83 300D.
The A/C appears to have been converted to 134A, i.e. the fittings are the same as on my wife's 2001 Subaru. No sticker under the hood making me think this may have been not professionally done. When I bought the car the dealer charged the system and the system was working for maybe two weeks. Now it is no longer working. There is a switch near the receiver/dryer. When I remove the connectors and short them together the compressor clutch does engage. I'm going to guess it's a low pressure switch. There are some new hoses leading off the R/D so maybe the job wasn't really done poorly and maybe I have just a leak someplace. Should a shop that services A/C be able to diagnose my problem without me spending 100's of dollars? Is the condenser a super expensive part, the evaporator? I found compressors for around 250~275 new which didn't seem too bad. Also does anyone have a step-by-step reference for recharging this A/C with 134A? I do kind of remember reading that 134A has to be charged as a liquid, i.e. can upside down if it doesn't have a pickup. What I am thinking is to get a can or so of 134A and put it in via the low side a little at a time and see if in fact the compressor does eventually turn on indicating that all I might have is a minor leak. I know there's a ton of stuff at this site, but I haven't found exactly what I'm looking for. Any help, guidance greatly appreciated.

We do conversons all the time and frankly the sticker is a joke. If the car has the new fittings its safe to assume that it has 134 in it.

Why would someone charge the system with R12 and then put the new fittings on?

If the system isn't working and you jump the low pressure switch it seems as if the charge is low. You said it was just done so I would say its time to get it to a shop that has a leak detector and find the problem.

Toxicant is correct. There must be a leak. Don't worry about the large condensor, you should not need it in your climate, just get someone to find and repair the leak then recharge. Should be no big deal for an A/C shop unless the leak is in the evaporator.

Good luck,