A/c Issues On 2000 Sierra

nnrice0812 · July 21, 2008

I have a 2000 GMC Sierra 5.3L with about 130,000 miles. The problem that I am having is that my A/C clutch will engage when the truck is turned on and the A/C works perfect but after about 10-20 min. of driving the A/C will stop blowing out cold air and will blow hot air that has a smell of melting ice. If I turn off the A/C and wait about 5 min. then turn the air back on, it will get cold and will stay cold for about 10-20 min but will stop blowing out cold air and will blow out hot air. This cycle does not happen early in the day but when the temp outside is around 90+ the issue mentioned happens.

Today, I started the truck and ran it for about 10 min. and checked the freon levels and they are normal. I also checked the A/C relay and all the fuses associated with the A/C system. I noticed the that the A/C clutch will engage but when I push the button to turn off the A/C the light goes off on the control panel but the air is still cold and the A/C clutch is still engaged. I am not a mechanic but figured that if the clutch is constantly engaged then when I am driving the unit will freezes up b/c of the high temperature outside and the constant running of the system? It also seems like this could be an electrical issue???

Any ideas???

Fortune50 · July 22, 2008

May have a faulty low pressure switch, rap on it next time (should be in the dryer) or simply bypass it by using a jumper wire and see if the system stays cooled down. If so, then replace it. BTW, this is bit of a common problem, there is a GM bulletin (TSB) out there describing this problem...