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Verified ground is good on plug to compressor. It does have 5 volts to the plug constant. This is as far as.I got
 

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Discussion Starter · #3 ·
Constant power to the compressor

I have a constant 5 volts going to the compressor key on or key off. Possible causes? Help please.
 

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I've merged your threads and moved it to the problems forum. It should get more attention here.
 

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Fcm

I have a constant 5 volts going to the compressor key on or key off. Possible causes? Help please.
IT'S either the fan control module or the compressor itself is bad. jumper battery voltage directly to the compressor plug and see if it comes on. If it comes on then disconnect immediately. Hook up A/C pressure gauges to see what your low and high pressures are.( my guess is they should be equal to around 90-110 psi sound normal to me) or measure the compressor plug with ohm meter and see what you get, should be low resistance 4-8 ohms.
 

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IT'S either the fan control module or the compressor itself is bad. jumper battery voltage directly to the compressor plug and see if it comes on. If it comes on then disconnect immediately. Hook up A/C pressure gauges to see what your low and high pressures are.( my guess is they should be equal to around 90-110 psi sound normal to me) or measure the compressor plug with ohm meter and see what you get, should be low resistance 4-8 ohms.
You can skip the battery step and just hook up a/c pressure gauges. Will be helpful if you have a buddy there to rev it up to about 2.5k to see if the clutch will engage or change pressure. You should be able to hear if it is attempting to engage and your RPM will change.

If no pressure change, probably the compressor. They seem to go around 50k miles.
 

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pressure change

You can skip the battery step and just hook up a/c pressure gauges. Will be helpful if you have a buddy there to rev it up to about 2.5k to see if the clutch will engage or change pressure. You should be able to hear if it is attempting to engage and your RPM will change.

If no pressure change, probably the compressor. They seem to go around 50k miles.
You won't see any pressure change in the gauges if the compressor clutch is not engaged. The only pressures you'll see is the equalizing pressure, which if normal will be around 90-110 psi on both gauges like I specify already. If the system is very low on Freon it will also keep the clutch from not engaging to avoid compressor damage. I must have been lucky cause mine lasted 150k miles.
 
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