XJ XJ6 / XJR6 ( X300 ) 1995-1997

Strange compressor happenings

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Old 09-25-2010, 08:55 AM
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Default Strange compressor happenings

Hi all,

Iv had this problem for a while now but only yesterday did i have a chance to investigate it. The air con compressor seems to be stuck on. I can move the centre section by hand when the ignition is off but as soon as i turn the ignition on, i cant. I have tried pulling the fuse for the clutch but this makes no difference and i have also tried pulling the relay but im not sure which of the relays behind the right hand headlamps are for the air con clutch (not that any of them made a difference).

I did notice that the little wire going to the compressor (i think it was red) has battery voltage when the ignition is on whether the fuse is in or out.

Does anyone have any ideas as im pretty much out?
 
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Old 09-25-2010, 04:01 PM
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The car is obviously switching on the compressor clutch when you turn the ignition on. I would not expect this to happen immediately so something sounds to be wrong. There are various sensors and a valve in the refrigerant line that could have failed thus giving a false demand to the compressor, hence switching the compressor clutch solenoid. However, taking out the fuse on the supply line should cut off the compressor clutch totally. Puzzling !!
 
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Old 09-30-2010, 01:18 AM
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I had another look today and it seems that the same fuse is also for the alarm sounder (the beep when we lock and unlock the car), that also works without the fuse in. I have traced the wiring from the fuse box to the compressor and all seems fine so i am stumped!
 
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Old 09-30-2010, 01:51 PM
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Anybody else here got any idea ?

I think our OP will have to track back with a multimeter to see where the mysterious volts are coming from.
 
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Old 10-03-2010, 03:13 PM
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I realy think you must be looking at the wrong fuse..

Otherwise the service manual exist for downoad in FAQ
 
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Old 10-05-2010, 06:46 AM
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Originally Posted by jaggachafen
I realy think you must be looking at the wrong fuse..

Otherwise the service manual exist for downoad in FAQ
Thats what i am starting to think. Just seems a bit strange that the fuses next to it are the same as what are in the manual.

Ah, well. Another job to do this afternoon.

I have just unplugged the compressor for now and the fuel consumption difference is quite shocking (up to 5mpg!)
 
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Old 12-10-2010, 03:12 AM
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Hi guys,

I spent yesterday (quiet day at work) inspecting all the wiring and someone (previous owner) had bypassed the fuse by taking a feed from the windscreen washers. What is worse is all they had done is cut the wires, twisted them together and covered in insulation tape! [insert mad smiley here].

Anyway, i have now sorted the wiring and the clutch doesn't work at all. I have tried a different relay, control panel and all the wiring seems ok. Also, i did some research yesterday and it seems the radiator fan shouldn't run constantly? Mine has ever since i have owned it.

If anyone could shed some light on where to look next, i would be very grateful.

Cheers
 
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Old 12-10-2010, 07:45 AM
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Haven't looked at the schematics....but many maufacturers, and specifically Ford, engage and disengage the comp. clutch by using the ECM to ground the comp when conditions are satisfied for its operation. Obviously more at work with your car given the "field engineering" you discovered, but it may not be entirely wrong for a "hot in run" lead to be going to the compressor. Obviously, if it is operated via the computer grounding it....the plug at the comp will be a two-wire.
 
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Old 12-10-2010, 09:06 AM
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The plug at the compressor is only one wire.
 
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