hfd11

Here in the south west Texas a/c is needed. This is what I know, static pressure 90 both sides, out side temp 85, low pressure when running 45, high pressure 220 with vent temp 50 degrees at idle and 40 when driving. There are 3 switches ( per parts available), one on dryer/ accumulator, one on the high pressure hose between the condenser and the evaporator, and the one on the back of the compressor ( no schader valve) . What I have read, since this system uses a constant flow orifice, that Freon is regulated by the clutch cycling switch. With all pressures in the right range, and only freezes when it is a cool morning or rain, I believe it is the cycle switch. When I go get the part, they call the compressor cut off switch is by the accumulator which I would think is the low presser safety switch. Please help with telling me which switch is which and what else I need to look for. Where does the cycling switch receive information from to cause the cycling. Thanks

hfd11

Sorry, this is 2001silverado with 178k miles.

MDTAHOE

Does the compressor cycle on and off at all? If so What are the pressures right before it cycles? Was any ac work done recently?

Allan In NE

Shut the hood and forget it. All you're seeing is the high humidity of the ambient air.

With those readings, your system is operating as close to perfect as you could get.

Allan

hfd11

The compressor does not cycle off and on when the a/c is on, just stays on when the a/c system is on, including when using the defroster. When the freezing occurred, the vent temp got warm and is why I looked under the hood and found ice on dry/accumulator. That was meant to be explained in original question. I believe the compressor should be cycling (a lot) during the cool mornings ( no more cool mornings any more). When I used the a/c on the hot part of the day, the a/c continued to blow cold as the cycling not needed. This is used truck just recently added to the family fleet for my daughter that lives about 40 miles from me, so I don't have much access to it and not aware of any repairs. There appears no be no dye in the system because the low pressure side Schrader valve leaks when at static pressure with cap off and I don't see any (have seen dye leaking out before on other cars). The pressures appear to be correct. No cycling of compressor seems to be the issue to me, Trying figure which switch/sensor and location. I recently have found out about an air duct switch/sensor inside the cab, does this sensor/switch cause the compressor to cycle? Is there a way that I may test the switches? Which switch is which on system, (on the accumulator, on the compressor, on the high presser line between the condenser and the evaporator). Temp selector in vehicle works, heater gets warm and cooler as selected. Thanks