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Need clutch switch help

aandy767 on Sun July 27, 2008 5:45 PM User is offline

Year: 2002
Make: Jaguar
Model: X type
Engine Size: 3.0l

Ok I replaced dryer o tube and compressor. rebuilt compressor.

This is a ford 3.0l DOHC made in Cleveland. Scroll type compressor. Same compressor frame as a lincoln ls.

Flushed and evac.

Holds a vacuum. Hooked up gauges and started to fill but can't find where to bypass the low pressure switch. I can trace the low side to the compressor, and can't find a switch.

There is a switch on the high side that turns on the fans.

Question???? Is the switch on top of the compressor? If it is I can't see it.

Question??? Can I take a lead from the hot battery post and turn on the clutch? or is that too many amps/volts?

Question??? While jacking with this stuff the system took one 12 oz can. 120psi per side. If I get the compressor to pump will I screw any thing up?

iceman2555 on Sun July 27, 2008 11:14 PM User is offlineView users profile

Am I mistaken....thought this was a TXV system? If so, the cycle points of the system are controlled by the evap temp...not a LPCO.
With a 'static' pressure of 125 psi..the clutch should engage, unless there is a possible electrical problem elsewhere.
Most scroll compressor do have a 'high temp' sensor on the compressor case....was this replaced....or was the one in the rebuilt compressor left in place....could be a bad sensor.
May be necessary to pull a wiring diagram for the system to determine possible voltage area problems.
Direct wiring the compressor....could be done...suggest to make a harness for the compressor clutch terminal.....remove the OE connection to the wiring harness and then attach the 'jumper' for activating the clutch. This should be done only for activation for testing purposes only....serious compressor damage could occur if this 'jumper' is left in place for an extended period of time.
Also.....why was the compressor replaced? Did it suffer a severe is possible that the condenser of this vehicle maybe restricted......and the condenser may need to be replaced.
The best method to insure proper clutch activation would be to have the system recharged complete prior to clutch engagement. Scrolls have many small roller bearings that are very susceptible to damage from lack of lubrication...this lubricant is controlled by the amount of refrigerant within the system....gotta be fully charged...or it is going to fail.....

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aandy767 on Mon July 28, 2008 12:23 AM User is offline

aandy767 on Mon July 28, 2008 12:29 AM User is offline

put an orange ford o tube in it.

only switch I can find is on the high side with three wires, one starts the fans and the other kicks up the idle.

Jag forum guy told me how to pull the clutch relay and jump it to work but not joy. I'll pull the compressor and check the wires into the compressor.

compressor was locking up above 2500 rpm. pulled it and had it rebuilt. replaced dryer o tube and flushed.

I knew it was all going to easy.

mk378 on Mon July 28, 2008 12:27 PM User is offline

Three wire "switches" are almost always sensors that feed a signal proportional to pressure to the ECU. The ECU analyzes that signal and decides when to turn on the fans, shut down the compressor, etc. You can't jump them.

Normally you don't have to jump anything to charge a system. Charge liquid into the vacuum until it won't take any more. This should be enough for the compressor to start normally unless there is a control problem. You could also have a shop do it with a machine that forces the complete proper charge in with the engine off.

You can jump the compressor wire to the battery to see if it will engage. Best to do this with the engine off. If you do it with the engine on make sure the condenser fans are running first. Running the compressor without the fans will cause an almost immediate, severe overpressure situation.

Chick on Mon July 28, 2008 2:30 PM User is offlineView users profile

Does this car have ATC? if so it may also have a code stored preventing the system from starting..As mk378 stated, DO NOT try to jump the pressure transducer as you can damage the ECM...

Email: Chick


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aandy767 on Mon July 28, 2008 10:20 PM User is offline


It was running when I pulled it, so I didn't think to look there.

blows cold


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