1990 GMC


Ego Racing

June, 10, 2007 AT 10:36 PM

We have a 1990 GMC Top Kick with a 5 speed and 2 speed rear. The Question I have is with the AC system so I am hoping you can help.
Right now the AC is not operational, when you Start the truck and try to turn it on the AC indicator on the control flashes and the fan comes on.
If I disconnect the battery for about a minute and re connect, start the truck and turn the AC on it blows very cold air and will run for several hours without a problem. BUT when you try to drive the truck it will stop within a minute of leaving the driveway, the AC compressor stops operating and the AC indicator on the control starts flashing. The only way to get it working is to disconnect the batteries again.


2 Answers



June, 12, 2007 AT 5:33 AM

Sounds like youre A/C button switch is not good, Needs replacing, Or the A/C relay unit wornout.



January, 7, 2010 AT 10:57 PM

I think you have an APADS system. You need to locate the controller and see what light is flashing. You are probably low on refrigerant if it will sit there and cool, but quit at higher RPMs. You could also have a bad low refrigerant switch.

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