I have 1992 C2500 With 7.4 liter engine automatic. The a/c just all of a sudden will not turn on compressor. I have checked the fuse and that is good. what next and where is the location of that part to be diagnosed. Compressor is fine.
Besides the fuse panel by the drivers lifet ankle, there's a fuse/relay box under the hood. In my 1998 1500, it's located by the fender, next to the brake fluid reservoir. I can't open mine more than an inch. It's hinged at the front, but the top of the fender prevents it from being opened all the way. I think the fuse inside the vehicle only protects the fan.
If the system is low on Freon the compressor won't come on . This is just a general a/c answer but there is a pressure sensitive switch on one of the Freon lines , I've seen it jumperd or shorted out to check the compressor , if it kicks in it's either low on Freon or the switch itself is bad. Don't do this for too long as the switch is to protect the compressor when the system is low. Hang in there winter is coming !
Don't have them, even if you had them ,it sounds like it needs a recharge . Seems like most cars around then used R12 , kinda hard to get a hold of. Check into doing a conversion to R32 maybe ?
You must have a proper refrigeration gauge set to correctly service any AC unit.
Look on the face of the blue gauge. You'll see there are scales on it besides the pressure. Those scales are noted for type of refrigerant and show you the normal temperature for a particular gas at a particular temperature.
Let's say it is 80 degrees outdoors and you hook the hose to the low pressure side of the system. The needle should be pointing at 80 degrees on the scale marked R12. If it isn't, and reads lower as is the usual case, then you don't have a single droplet of Freon left in the system. This is done without the engine running or the compressor engaged, of course.
Once you have the system running and well charged, the correct pressure is the one that corresponds approximately to 30 degrees on that scale while the compressor is running. At that pressure/temperature no ice will accumulate on the coil inside the vehicle.
Also look around and find the sight glass that most R12 systems had on them. You can watch that while charging and the correct pressure/temperature should be achieved at about the same time as all bubbling in the sight glass disappears.
There are no "normal pressures" for the high and low sides in the context of some single small range of pressures being correct because refrigerant systems are saturated and pressures are temperature dependent when not operating.
GM was using CCS ie Clutch Cycling Systems with R-12, so was Ford, and most of the "better" imports(if there is such a thing) My 87 and my 91 Chevy where both R-12 from the factory, and nether have sight glasses. Type of refrigerent has nothing to do with it.
Quit bickering over a post that the original sender has probably moved on from. They were told they have a problem unless they ask a question specifically about what has been posted let it go. From the information that was given they fixed it this weekend and have forgotten about, never to be heard from again.
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