How to jumper low pressure switch

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How to jumper low pressure switch

Postby Kestas » Tue Jun 28, 2016 4:52 pm

2008 Dodge Grand Caravan 3.8L

The clutch isn't engaging when I turn on the a/c. I found the low pressure switch at the receiver. It has three wires going to the switch (blue - blue/orange - blue/black). Which do I jumper for a quick check of the clutch coil? Or could I just try a combination of all three without creating problems?
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Re: How to jumper low pressure switch

Postby cornbinder89 » Tue Jun 28, 2016 4:57 pm

No! wait for someone who knows you system. It looks like it may be ECM controlled and you could fry expensive parts by shorting things together.
I don't know your system so I would wait until you know for sure what to do.
Do you have gauges on the system? what is the static pressure reading?
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Re: How to jumper low pressure switch

Postby Tom Greenleaf » Wed Jun 29, 2016 9:32 am

Just don't jump HPCO switches - ever. Chryslers use an ECM that even controls alternator for voltage and more all in one you can blow.

Just OHM test clutch coil (engine off and by itself) for ~4.5 or real close. If 12v detected go on to check the air gap almost universally should be about .020 gets larger over time but will quit engaging at some point.

Pretty sure this and many systems will shut down if engine heat too high and other assorted reasons and not come back on till reset by sometimes a trip to a dealer.

Chance of a battery disconnect will start over default settings not suggested in general. You lose all info stored, alarms may be activated and engine controls forget adjustments made over a period of time and might not run well for some time.

Rule out the basics beginning with static pressure as cornbinder89 just mentioned. If lower PSI than temp in F. it's too low on refrigerant to operate and you should seek help or get ready to find the leak and how to fix it,

T
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Re: How to jumper low pressure switch

Postby Kestas » Fri Jul 01, 2016 6:34 pm

I put the gauges on and get zero pressure. So, it's lost all refrigerant.

Can anyone tell we if UV dye was put in there from the factory?
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Re: How to jumper low pressure switch

Postby Tom Greenleaf » Fri Jul 01, 2016 7:09 pm

Double check you are really reading ZERO and not a problem with hook up or gauges. It could be good news that this leak is so fast you wont need much to find it - maybe even hear it?

T
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Re: How to jumper low pressure switch

Postby Kestas » Fri Jul 01, 2016 7:32 pm

I'm pretty sure it's zero. Not even a hint of a momentary hiss when connecting the gauges.
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Re: How to jumper low pressure switch

Postby Tom Greenleaf » Fri Jul 01, 2016 8:24 pm

I trust you just do make sure. I've had many couplers that just don't push the pin just right and another set of gauges did?

You are right the just hooking up like even tires checking pressure you get a momentary hiss,

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