Johnson797

So, my compressor doesn't kick on by itself. The main wire coming into the back of the compressor has 12 volts to battery neg. Compressor clutch will kick on if I run a jumper from battery positive to the compressor side of the connector. After discovering that, i figured the connector was bad so I cut that out and butt spliced it but it didn't help anything. Fuses are good, relay is good, high and low pressure switch are functional, refrigerant pressure reads good, I tried vacuuming it down and recharging, still nothing. Clutch isn't sticky, it turns easily by hand. Electric fan kicks on but compressor doesn't. Not sure what else could be wrong. I really don't understand how the connector is getting 12 volts, but won't kick on the compressor, but 12v from the battery will.

agreen

When current flows through things, it can cause a high resistance connection as it heats up. Try swapping the AC relay with another one in the power distribution block (temporarily) to see if the contacts in that relay are going bad. There isn't much in that circuit.

https://www.justanswer.com/jeep/37nv...g-diagram.html

Johnson797

I have tried that also. Although it was not a new relay, i still got the same result. With both relays i could feel them click on as i plugged them in.

agreen

Something in that circuit is dropping enough voltage to prevent the clutch from engaging. With the compressor unplugged, you're getting 12v because there isn't a complete circuit. See if you can use a paper clip or something thin to back probe your butt splice connector and check the voltage going to the compressor with the circuit complete. I'll bet it's not 12v.

Johnson797

Thanks, didnt specify that I got 12v between battery neg and the connector from the car side. But I will try to meter it with a complete circuit later today.

Johnson797

Another thing I should add; I tried charging the system while my jumper was in place from the battery with the compressor running, and the system wouldn't take any refrigerant. It only took like 3 seconds to fill the system to the green level on the trigger pull guages that come with the r134 cans.

awg

If you say directly connecting 12V from battery makes it work, and you are receiving 12V from the relay, you could fault find by using a cheap Bosch relay in between, with 12V from battery and triggered by other relay. My guess is not enough current is getting through relay or wire to power up compressor, which takes a lot of current

If this is the fault, this temp fix could also be a permanent cure if ur lazy

Johnson797

I'd rather not use that as a permanent fix. Shoddy wiring is what caused this in the first place since the car is a salvage title. The whole harness has been redone by some yokel and I've found random connectors hanging, wires just wrapped around each other with a ball of tape, etc

Roler

Always thought that was stock from factory...

agreen

That's how my J10 pickup was from the factory. The coil wiring had a splice that was covered in silver duct tape, which fell off and shorted to ground while I was driving in a torrential rain storm.

Johnson797, maybe try using a test light. My previous point may have been missed, so try using a regular old test light to see if you're getting power at the connector. If the connection up to that connector are good, your test light will illuminate. If not, the light won't turn on, but you could STILL get 12v by multimeter reading.

awg

Even though its meant as a diagnostic, it wont be a shoddy fix

As member agreen noted, 12V voltage means nothing if its only a few miliamps

someone has added FIVE relays to control my headlights, **** knows why, but it works, and I dont want to rewire everything.

Jeep wiring is ****

Johnson797

A test light does illuminate at the connector

Johnson797

I'm also only getting .5v from the completed circuit to battery neg

Johnson797

I'd greatly appreciate if you could explain this relay trick more. Can I just use any 4 pin relay?

Johnson797

Drawing less than .2 amps also