jsbigone

A 1992 g20 van I just bought has a rear a/c blower switch on the dash. I see no rear a/c unit, and I tried to order a new a/c compressor cause the comp is wasted. They asked me if I have rear a/c.

So what i'm asking is did vans come with rear blower switch that didnt have A/C in rear or is it standard to have rear a/c if you have switch?

Thanks
Big John

RacerX

1. How do you know your compressor is bad?

2. I have a 1993 G20. Does your switch say REAR A/C? Mine says REAR HEAT.

I would think they offered this as a convenience group. The heater core and a rear evaporator. This is a vacuum operated climate control. There is a vacuum diaphragm attached to the heater control valve so when the dial on the climate control in in the blue COLD zone the hot coolant is shunted back to the radiator and not to the rear heater core. But in the COLD setting there should be air diverted past an evaporator.

I just came back from the airport and it was cold up front but smoldering in the rear. I dont use the switch because it says REAR HEAT. BUt in my Suburban it only says REAR CONTROL. The fact that the switch is there means there is a unit in the back. It is basically just a sticker that goes around the trim ring but I have got to see if there is a Rear Evap back there. This van would be unbearable for rear passengers if it doesnt have one. Those 4 small vents in the front cant do enough to cool this thing down.

It would also explain why charge capacities dont equal what they should be for this car. Single evap system should be like 3lbs R134a extra evap almost doubles capacity to a little less than 5lbs. In my Suburban it is ice cold from the back and cool in the front. In the G20, I measure charge by compressor cycling time(old Ford method).

Suburban was originally R-12, G20 was R-134a when I got it. Both are 1993, but I dont know when....

I m going to write another thread about this R-12 replacement I came across. R-12a from Enviro-Safe. I bought a case and so far, in an empty R-12 system I put 5 cans(6 oz.) in the Suburban and 2 in the G20. It is miscible with the other stuff. Different molecule. They want you to use only 35% of what you would use in an R-12 and 30% of what you would use in an R-134a system. Plus I added to both trucks a 4 oz can of oil and leak sealer. So far as hot as it has been this summer, the Suburban had paid off when it dark(less solar radiation) and the G20 is ok as long as it is not TOO hot(in the 80s).

They recommended for larger cars to put Industrial 12a instead of Regular 12a. I guess it has greater thermostatic qualities.

Well, I m going outside and will sit in the van for a half-hour. I will put the REAR HEAT **** on max and see if the van gets ice cold.

RacerX

Nope. No Evap in the rear. I dont get it. This van was an airport shuttle bus. How do you run airport shuttle service with no rear AC?

jsbigone

Racer I'm sorry buddy I didnt get back here! I'm disabled and cant get alot of work done and it was a hotter than hell summer here. Well also I got too many toys to be workin on!

My switch up front just says rear blower. In the right side wall at rear I found a Heater, AC condensor, with a with a temp controlled expansion valve.

It is an after market I presume. because it has 2 heater control valves in the front area, and also in the lines underneath going to the back is shrader valves, but its just to check the rear unit pressures. It all runs off of the front unit.

I was only gettin heat back there cause the heater control valve was stuck I think so I put an exterior valve cut off in the line going back to rear that I had laying around. So that shut off the heat back there and now blows cool, not cold, but atleast no hot air coming out back there. I need another can or can and a half of r134 and I think maybe it will be cold air comin out.

After a hellacious summer here, were getting some 80 degree wheather now so I'll probably wait till next year. The front blows real nice and cold.

I'll let you know how it comes out.

Big John

RacerX

Probably a factory unit.

I had a problem with my Suburban last week when we had that hurricane. I went to Walmart and it was warm up front but cold in the back. This car was built as an R12. I put R134a connectors on it and apparently the pin that is supposed to push down the Schrader valve when you charge it up stayed depressed with the connector on. So all the gas I put in would leak out through the charge port. Then I would remove the cap and it was have all this oil in it because it was slowly leaking out. So what I did was to use the connector to charge another 2 cans into the system to fill it up again. And then remove the low side R134a charge port.
I drove 220 miles roundtrip from NY to Allentown today and although it wasnt ICE cold in the front it was incredibly comfortable. I look for another low side charge port before it gets cold and put maybe one more can in there before winter and we will see what it looks like in the spring time.