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A/C Help - Chevy Venture - Where is Low pressure switch?

Our A/C on our 2003 Chevrolet Venture van started blowing only warm air. I checked the pressure and there is coolant in the system (I checked pressure with a guage on one of those hoses you get with the can of R134, didn't put any R134 in and it reads about 100 psi on a

85 degree day). The compressor is not coming on, fans are on. Fuses are ok. But I cannot find the low pressure switch. Does anyone know where it is ont these vans?

I found one switch/sensor underneath the air box on the A/C line, but this has 3 wires, I thought the low pressure switch had only 2 wires.

Any other thoughts on what it might be, common problems? Hoping its not the compressor or compressor clutch.

Again, its a 2003 Chevy venture with rear Air.

Any help is greatly appreciated.

Thanks.

Lee

Reply to
Lee
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You found the pressure sensor (not switch) that GM uses on their A/C systems. It is a three wire transducer that has 5v reference, ground, and a return signal wire to the PCM. The easiest way to check this function of the system is to read A/C system pressure on a scan tool. Any properly equipped shop would start this way, then go to component diagnosis if the scan data showed a problem with the pressure sensor.

The PCM actually controls the compressor clutch on/of function. It does get it's command to turn on from the HVAC module, which takes the dash controls and evap temperature into consideration.

If you don't have access to a scan tool, you can first check the compressor plug to see if voltage exists when A/C is commanded (engine will need to be running, so perform this test carefully).

Toyota MDT in MO

Reply to
Comboverfish

Hot wire the compressor to test it to see if the clutch and compressor are working. If it comes on you can get a reading with your gauge and see how low it's pulling.

Reply to
Ashton Crusher

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