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, didnt 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
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Disconnect the connector to your compressor. Turn on the ignition to the run position and check for battery voltage at the green wire pin. If you have voltage here, the problem is in the clutch/compressor.
If not, the problem is upstream and probabley in the relay or swithch. The relay is located in the fuse panel under the hood on the right side in my 2000 Venture. You will need a multimeter and jumpers to check out the relay.

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Thermal Limiter & Superheat Switch is a 3-wire device that stops compressor operation. If that is the cause of the compressor not operating, the system pressure problem that caused it to melt the fuse, needs to be corrected before replacing the switch. It is a pretection device for the compressor.
Dave S(Texas)
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On Jul 13, 11:49 pm, snipped-for-privacy@home.com wrote:

Sorry I didnt respond sooner, I didnt think anybody responded to my post. I did find a fuse blown in the under hood fuse block. It was a fuse for the compressor relay I believe. Once I replaced it, the compressor started working again.
But now, we get barely cool air, but nowhere near as cold as it should be. I haven't re-checked the r134 level, but am wondering if for some reason it is low, now that the compressor is working again. And I have noticed that the driver side blows considerably warmer than the passenger side. This all is leading me to think that there is some other problem somewhere.
Other than low r134, the compressor is working, is there anything else in the system that could cause the air not to blow cold? (A "blend" door not working or something like that?)
Thanks again for your help.
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