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How can I manually jumpstart A/C compressor bypassing the pressure sensor?

06-24-2005, 06:02 PM
How can I manually jumpstart A/C compressor bypassing the pressure sensor?

I have seen a piece of wire being placed to shorten some electrical contacts by the compressor, but dont know how to do it exactly.

Any help greatly appreciated.

06-25-2005, 01:45 AM
The low pressure sensor is in one of the a\c lines that goes to the evaporator inside the vehicle. It has a two wire connector. You would pull off the connector and stick a wire inside the connector shorting the two wires together. The low pressure switch is usually on the suction line somewhere between the compressor and where the lines go into the firewall.

HOWEVER. If your compressor is not coming on because the low pressure sensor is tripping off, then you can damage your compressor by jumping the sensor. If your vehicle is low on freon, your compressor will not receive enough lubricant that is carried along by the freon and compressor failure will surely result.

If you just want to test your clutch for a few seconds, it might not damage your compressor for a few seconds, but to jump it permanently surely will.

If you are low enough on freon to trip the low pressure, then your a\c won't work good enough to cool even if you jump it.

Of course if you jump the HIGH pressure switch, and your compressor has to much freon, then something could rupture, causing damage to your system, as well as possibly injuring somebody.

Of course you could be asking for a totally different reason that I am totally unaware of. But I just wanted to make sure to cover the bases.
Hope this helps.

06-26-2005, 12:31 AM
Thank you very much mikmic2.

Will post further questions if any.

03-14-2010, 01:30 PM
MikMic2 - Can an auto A/C shop check these type of switches to determine which one lkeeps the A/C compressor from cominh on or do I need to find an A/C shop? My mechanic told me that the system works finewhen he bypasses the compressor manually (I assume he was speaking about the low or high pressure switch - not sure).:confused:

03-15-2010, 12:11 AM
You need to find a better mechanic. Any good shop will be able to follow a factory service manual diagnostic and find the cause to your problem. Jumpstarting the AC clutch and then returning the car is no fix. Yes, they can run tests to find out what is wrong. The majority of the time when your clutch won't engage your refrigerant is low. Usually it is caused by a leak, thus adding more refrigerant is not the answer, but rather finding and repairing the leak first IS the answer.

It may be something else, such as a switch, wiring, or AC controls, etc.

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