A/C malfunction

[RockyinNJ]

I searched and no answer. I notice that my AC blows cold air when its 70 or below (outside temp). Then it blows vent type air (cool not cold ) when the outside temp is above 70 degrees. I am yet to get consistent cold air. Should I take in to the dealer or is there something I can do to fix this problem?

[jnenad16]

you might be out of freon, meaning you might have a leak. take it to a shop and have them check the system pressure, if the pressure is good, then the most likely problem could be a sticking expansion valve. dirty filter/drier or blown compressor could also be the problem. or it could be something simple as the compressor clutch not engaging due to a blown fuse of relay. however, the possibilities are not limited to any a/c system component.

nenad

[Jasonmarosi]

Wheres The A/C Relay? I found the fuses.

[BillKerler]

Hey Nenad
In auto climate control on my 94 c280 I have an intermittent problem. I hear a whoosh sound from within my dash console and the cool air goes away, yet I have done nothing to initiate this. It's the same sound when you change from auto to ec on a warm day.

When I lower temp setting to 52, press rest for 6 seconds and enter into the diagnostic circuit for climate control, setting #5 for evap temp sensor slowly but steadily starts climbing from 52 to 102 if it's hot enough outside. All other diagnostic readings look good.

The clutch remains engaged on the compressor. My suction and discharge refrigerant pressures are ok (like 38 suction and 170 discharge). I cringe at the thought of replacing an expansion valve. Is the thermal bulb on the expansion valve the thing that usually poops out? I have had other temp sensors on this car using a thermal bulb that go goofy on me...I usually remove the bulb from its mounting location, put a cigarette lighter flame under it, get it very warm and then flick it with my fingertip and that usually wakes it up to work again...for how long is anyone's guess. Is the expansion valve temp bulb able to have something like this done to it? What's your experience? I really have trouble comprehending how a valve can stick, but I can relate to a bulb getting flaky...not working. Where exactly is the bulb mounted? How hard is it to access?

Bill Kerler