A/C compressor won't click on- anyway to jump it to see if it is still working?

[01eddie]

trying to figure out if it is broken or if it isn't clicking on because of low pressure, etc. Any hints? 2nd gen, 5.0

 

[Mud_Bone]

Remove the plug in on the low pressure switch mounted on the accumulator (near firewall / passenger side fender area)and jump the two wires in the plug in. Compressor should kick on and run, but dont run it very long until you find out the real problem. If you have a set of A/C gauges, have them hooked up and check the pressure while doing this.

 

[01eddie]

Got Compressor to click on... now what

O.K., if I jump the plug on the while the a/c is set to Def. then the compressor clicks in. If the controls are set to Vent, nothing happens. I had a helper check for cool air wile the compressor was rinning, but didn't feel a change. Don't now if there would have been anyway with the plug disconected from the condensor.

what is the big black box half covered with foil directly behind the accumulator? The condenser?

What should I check next? any advice?

 

[TheJackal]

O.K., if I jump the plug on the while the a/c is set to Def. then the compressor clicks in. If the controls are set to Vent, nothing happens. I had a helper check for cool air wile the compressor was rinning, but didn't feel a change. Don't now if there would have been anyway with the plug disconected from the condensor.

what is the big black box half covered with foil directly behind the accumulator? The condenser?

The foil-covered box is the evaporator case. Your evaporator is inside.

The A/C compressor does not turn on in "Vent" mode. That is normal operation. The A/C compressor will run in all other modes except "Off."

 

[DeRocha]

Is the a/c system charged/under pressure? Along with the refrigerant the a/c system contains a lubricant for the a/c compressor. As such if the system is no longer charged/under pressure the low pressure safety switch prevents the compressor clutch from coming on and seizing the A/C compressor.

 

[01eddie]

So my next step would be to try to find out the pressure of the system? what kind of guage works for that? or should I try to charge the system? Do those kits from walmart work or should I take it in?

Also, I thought it worked fine this spring, but it wasn't real warm out- really late spring up here.... if it lost coolant in a hurry where would be a good place to look for leaks?? I assume If I put coolant in it would be hard to see were it was leaking out since it is a gas inside the system??

Thanks again for all the help- I'm a real noob at HVAC. diagnosing is my biggest challenge at the moment.

Brian

 

[Gaximus]

Ok I'm having the same problem. when I turn on my car the A/C compressor turns on for 2-3 seconds then stops and won't turn back on at all. I've tried useing a jumper on the low pressure switch and the high pressure switch(and every possible combination.

Even If I turn on the engine then use the jumpers after the engine is running it won't turn on after it has been running.

Any Ideas? please help

 

[scooter78]

I have the same problem. 1999 Explorer 4.0L After turning the car on the compressor cuts on and runs for like 5 sec. then disengages. Were you able to figure anything out?