'94 c220 A/C problem.
 

My AC on my 94 C220 only works intermittently. If it's really warm & humid, only warm air blows out of the vents. If the temp is reasonable, I get cool air coming from the vents. I just had the system recharged, so it has a full load of R134a, and the compressor is OK.
Does anyone have an idea of what the problem may be?

Thanks
Darko

Did you have the system checked for leaks? It sounds like you're low on freon (again) - I'd get yourself a set of R134 gauges and check the low/high side pressures and report back to us what they are.

I don't think it's a leak. I had it recharged 2 days ago. Even during the recharging process the compressor wouldn't kick in.
Last night, while going to work, I had no AC. The outside temp was around 35C and humid. This morning, on the way home, the AC was working. Temp was around 24C and a little less humid. When I pulled into the driveway, I popped the hood, and could see that the compressor was running.
It makes me think that the problem is electrical in nature.

It sounds as if the compressor, or the control of the compressor is not OK. I would do a search on the climate control unit and look at testing the compressor engagement circuit. I thought it was low on refidgerant because low charge will often exhibit inadequate cooling on hot days but moderate/adequate cooling on cooler days (or on lower blower speed)

There is much more involved with having cold air than the compressor and charge. There are a zillion things in the climate control system that can prevent you from having cool air even if the refrigeration portion is charged and working properly.

I don't know how to do so on the 202 car, but you need to find out how to check for trouble codes in your climate control system. On the 210 car it can be done at the control panel by pressing a particular button sequence and read the code. A factory service CD would certainly be a good investment and give you the troubleshooting procedure for this issue.

Good luck,