Question-------------------------
Followup To
Question - One last st of questions:
-Where is the pressure cycling switch?
-Does the A/C system heed to be evacuated to replace the switch?
-If you know, is this a dealer only part, or might it be found elsewhere?
Thanks.
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Followup To
Question - FOLLOW-UP: I have noticed that there is frost/ice on one of the hoses and its pipe and fitting as it leaves the compressor running to the evaporator core in the past. I told the dealer about that condition, but was told there was nothing wrong with the system (see original question)
With outside temperatures between about 70-83 degrees, after about 20 minutes, the blower will put out almost no cold air. I can hear the compressor cycling on & off for a little while, but I can't always tell if the compressor is cycling when I experience difficulties.If I turn off the compressor and wait until warm air atarts to come out (usually about 5-10 min), the blower output increases. I can then turn the compressor back on for another 20 minutes or so. I do not seem to have this problem whn outside temperatures are below about 70 or above 85, or when the truck is idling. I have also noticed occasions when the truck is parked after the A/C has run that I get a large outpouring from the evaporator drain, leading me to think that perhaps the evap. core is freezing up. The dealer has had the truck in and taken a snapshot of the system. A/C pressures and air temperatures are all in range. Any suggestions as to what the problem is greatly appreciated, as well as insight as to whether I might be able to effect repairs myself would be greatly appreciated.
The truck is a 2500HD 4x4 6.6l Duramax/Allison transmission.
Answer -
WHEN THIS SITUATION OCCURS AGAIN : With outside temperatures between about 70-83 degrees, after about 20 minutes, the blower will put out almost no cold air. I can hear the compressor cycling on & off for a little while, but I can't always tell if the compressor is cycling when I experience difficulties.
Stop the truck and lift the hood and see if any of the hoses and or the accumulator (receiver/drier) have any ice on them.
Without performing all the tests myself the only most common fault would be the PRESSURE CYCLING SWITCH which has always been problems with GM.
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Answer -
Replace the PRESSURE CYCLING SWITCH
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AnswerCheck with your local parts stores to see if they have it. If not, try your dealer. Once you buy it, You will know what your looking for. It is usually located near the accumulator near the firewall on the passengers side in the engine compartment.
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