It's a 1997 MC 3.1 and i want to force the AC compressor on. True i could have a leak or my fuses or relays are bad but none of these are happening. It was working fine 1 minute and now it's not. How do i force the compressor on. There is a sensor coming from the smaller ac line near the battery with 3 wires. What is this sensor called. Thanks......Tom

 

I'm not a tech, but I'm a searcher & I hope one of our many expert tech's reads your post & can help you with your problem....Below is the link I found....Check it `out & please check back on your thread later to see `if any of our helpful member's have posted...Good Luck & we hope you get it fixed & stay cool

Coolant Level Sensor by BWD - part# S8122


Feb 11, 2011 ... Air Conditioning Compressors; Air Conditioning Hoses; Air Conditioning .... Yes a coolant level sensor could be the issue in this overheating problem. .... 1997 Chevrolet Monte Carlo LS (engine: 3.1L 189CI V6 FI VIN: M ...
www.advanceautoparts.com/.../565315-coolant-level-sensor-by-bwd-part- s8122.html - Cached- Block all advanceautoparts.com results

 

I believe the sensor you are referring to is the pressure sensor. It keeps the A/C from coming on if there isnt any pressure in the system. You can pull the plug and run a jumper between the terminals to get it to kick on.

 

Thanks Kidspace but my "cooling problem" is not engine heat but AC cooling sensors. But thanks for your great suggestion and link to some parts i might have needed.

mrl390. My pressure sensor has 3 wires going into it so could you explain how to jump it please? Are these wires hot or grounded?...Thanks.....Tom

 

Yes there should be 3 wires in the plug. One wire is a ground, one is a reference wire and one is a signal. Put a multimeter on it and test the voltage to each wire. The one with 5 or so volts is the reference. You need the jump the other wire, the signal wire with the ground wire.

 

Matt...Key on, max air on, fan on. At one lead there was 5 volts, so i jumped the other two with the engine running and the compressor clutch did not engage, although the engine cooling fans did come on. I suppose they do when i jumped these 2 leads. My under the hood relay is good and any AC related fuses check ok. Anything i missed? I tested the wires going to the compressor with the jumper on and there was no voltage. I pierced the wires with my tester just out of the large harness.

 

i have the same issuse with mine, did you have any luck with it yet?

 

Those should be the correct two to jump. The fans are supposed to come on with the compressor so the PCM is at least trying to make the compressor kick on. With the key on and the wires jumpered, turn the A/C on and off. If your fans kick on when you turn the switch on and go off when you turn it off, your switch is probably ok. Your best bet would be to find a wiring diagram and go from there. Check if you have power going to the compressor relay and power after. Work your way to the compressor from there and you will probably find your culprit.

 

I would like to apply voltage directly to the compressor but i need to know how much voltage is needed. Any idea the volts needed to make the AC clutch engage?

 

I would assume 12 volts.