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View Full Version : Anyone in socal good with diagnostics on the AC system?


KingOfTheHill
August 5th, 2008, 09:30
I have been trying to diagnose it but cant figure it out..

quick rundown..

I turn the AC on and the blower works, the clutch does not engage and the volt meter on the dash drops HARD as if there is a short somewhere and then 5-8 seconds go by and POP the fuse goes.

SO... i applied power to the compressor directly and the clutch does not engage... damn... so i try and isolate the compressor as the short and unplug it.

so with it unpluged i put a new fuse in, start the xj up and turn on the AC... the volt meter drops hard again, blower motor still blows strong and then pop goes the fuse.

whats getting me is the compressor seem's bad since i cant trigger it directly, but the short seems further back in the system...

any advice? This is not a "MUST FIX" item, its not stopping me from driving, but i would like to have it working...ya know..

anyhow... any words of wisdom?

Thanks

JOe

FordGuy
August 5th, 2008, 09:38
Sounds like the field is shot. Do you have a ohm meter?

KingOfTheHill
August 5th, 2008, 09:41
Yes I do. not understanding Field?

JOe

cds36
August 5th, 2008, 10:09
Scott "Clean rc" or Dan "Gerr" I believe are really good with Ac. Not sure if they have the time but cant hurt to shoot them a pm

xjjeeper19
August 5th, 2008, 17:40
Yes I do. not understanding Field?

JOe

The field coil on the compressor clutch. You need to check the resistacne fron the Power wire to ground with the connector unplugged. This will tell you if it has an open coil circuit, or high resistance.


Justin

scottmcneal
August 5th, 2008, 17:50
Does your elec fan work?

Clean Racing
August 5th, 2008, 19:08
so i try and isolate the compressor as the short and unplug it.

so with it unpluged i put a new fuse in, start the xj up and turn on the AC... the volt meter drops hard again, blower motor still blows strong and then pop goes the fuse.



Lets start with the basics.. We know it blows fuses, so take a look upstream at the relay first. Then trace from there the low pressure switch ( I know its a real long shot-but still possible) I would start checking for a draw after that, maybe a wire has shorted itself to one of the wires for the a/c.. Just my insight right now..

KingOfTheHill
August 5th, 2008, 20:31
ok, got it... the module where the switch is was shorting out internally..

oddly enough i took it out of my other 89 my brother is buying to test it and YUP... i have AC now... Sweet!!!!!

thanks for the help guys... i just need to go to pick-a-part now and get a switch whatever module for my brothers now in change.

JOe