Looking for input in trouble shooting rear A/C only blows hot air on a 1991 Chevrolet G20 van Aero conversion. Once fixed, I will then post in “What did you do to your van today†section….
Here is what I know with the A/C.
1. Installed new compressor last year, R134a
2. Charged the system up to 4lbs.
3. Ran OK last summer (worked, but just didn’t have the power/cold of a newer vehicle, I know it’s 28 years old and there have been a few improvements in 28 years, I also understand the van is a large area to cool down on a HOT Iowa day)
4. As of last night, the front blows cold air when the AC is turned on, the rear blows hot air.
Here is the issue and what I don't know
1. The rear AC only blows hot air, at first, I thought the rear needed a little time to cool down
a. Blower works great
Rear air worked last year on the way to “Van Nationals and backâ€. First time using the rear air this year (last night) would only blow hot air. From reading your posts (I’m not a mechanic, but enjoy a good trouble shooting with a voltmeter) it sounds as if I may have 1 of the following causing my problem.
1. Valve up in engine compartment that is allowing coolant to still flow to rear, thus why rear a/c is blowing hot air.
a. Can a person shut this OFF? If so how?
b. Where is the valve located?
c. Does anyone know if that valve is vacuum operated or DC operated?
2. Could I have a bad “expansion valve†in the rear A/C?
a. If so, how does one test the expansion valve?
I would like to say the issue is #1 but would like anyone’s input before I tear into it this weekend and get soaking wet from the humidity this weekend.