Air Conditioning troubleshooting

K

KETCH-UP

New member
Can someone give me some tips on how to troubleshoot the AC system? The compressor runs and the air blows cold for ~10 minutes. Then the vents seem to close off and the fan sounds like it is deadheaded for flow. Then obviously I get very little AC . Anyone have thoughts on where to start?
 
syclone rider

syclone rider

New member
Re: Air Conditioning troubleshooting

KETCH-UP said:
Can someone give me some tips on how to troubleshoot the AC system? The compressor runs and the air blows cold for ~10 minutes. Then the vents seem to close off and the fan sounds like it is deadheaded for flow. Then obviously I get very little AC . Anyone have thoughts on where to start?
Click to expand...
I would say it was a vacum problem if the vents close by themselves!
 
Brassmonkey

Brassmonkey

Cruzin' Mel Man
Re: Air Conditioning troubleshooting

Sounds like to me the evap is freezing up or possibly the low pressure switch is kicking out the compressor, which means low refrigerant.
 
wildphil

wildphil

I Love My Ty's
Re: Air Conditioning troubleshooting

Were is the pressure switch located at please? I know very little about the A/C system.
 
wildphil

wildphil

I Love My Ty's
Re: Air Conditioning troubleshooting

Thanks Dave. I never would have found the screw if you wouldn't have told were it was located.
 
V6 Kompressor

V6 Kompressor

New member
Re: Air Conditioning troubleshooting

After all these years, i did not know that switch was adjustable... I guess that is why I hated working for STEALERSHIPS...., don't make an adjustment, sell them some new stuff that they don't need! also your freon level can still be low on top of the switch out of adjustment. FYI, if you have a vacuum problem, your vents, when selected on ac, when you give it the gas, the vents go from the dash to the floor/defrost, then you have an indication of a vacuum leak. The normal/no vacuum state is floor/defrost for most vehicles of this era, cept the c/k series trucks that had electric diverters...
 
S

sycam_steve

New member
Re: Air Conditioning troubleshooting

5678TA said:
hey guys, sorry to semi-highjack the thread but i'm doing a conversion to R134a since my compressor was shot and saw that the 93's dont have an adjustable switch... anyone know the PN on the adjustable switch? not sure but is this it?

http://www.oreillyauto.com/site/c/detail/MUR0/36674.oap?year=1993&make=GMC&model=Typhoon&vi=1164451&pt=01957&ppt=C0053
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I put a similar switch on mine and it made quite a difference the R12 Switch did not close at the low pressures that R134 had on the low side.
 
5678TA

5678TA

New member
Re: Air Conditioning troubleshooting

DaveP said:
That switch looks like it. But you will have to change the connector. Or use insulated female spade terminals.

There is a GM switch that works with the 93-up connector that is calibrated for R-134. GM P/N 52468323. The 134 switch has the word "green" on it. The R-12 has "black".

It IS possible to remove and replace the switch without loosing the refrigerant. The fitting has a Schrader valve in it. The switch has a little o-ring inside the recess. Make sure this o-ring is positioned correctly in the new switch. After you have it installed, turn off the engine for a few minutes. This will allow the low-side pressure to rise to about 80-100 psi or so. Then check the area around the switch with a dish-soap solution for leaks. Dab it on with your finger, wait and watch for bubbles. If you find a leak, double-check the o-ring.

I always check my work for leaks after I'm finished. Especially with R-12 systems.
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Thanks Dave!! I don't have to worry about the refrigerant, my system had a leak and there was nothing left.
 
M

mthurman04

New member
Re: Air Conditioning troubleshooting

I have a 93 and the compressor is shot. I just picked up a new delphi one. From what I'm understanding I'll need that new GM switch right because of the lower pressure? I just got this Typhoon and I'm assuming that it hasn't been converted yet.
 
J

Jetmugg

New member
Re: Air Conditioning troubleshooting

It's not necessary to change to r134 due to a compressor change, correct? R12 is still widely available, and definitely cools better than R134.

SteveM.
 
Brassmonkey

Brassmonkey

Cruzin' Mel Man
Re: Air Conditioning troubleshooting

Jetmugg said:
It's not necessary to change to r134 due to a compressor change, correct? R12 is still widely available, and definitely cools better than R134.

SteveM.
Click to expand...

I take it you do not live in the USA. R12 is harder to find than hen's teeth here and costs a small fortune when you do find it.
 
J

Jetmugg

New member
Re: Air Conditioning troubleshooting

I do live in the USA, and have a 20# cylinder of R-12 in my garage. There's no shortage here.

Check Ebay, there is plenty of R12 available. The higher cost of R12 (perhaps twice R134's cost) is a small expense in order to achieve a factory-correct air conditioning system.

SteveM.
 
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