Anyone out there a master A/C tech?

[86 TR]

Im working on a 01 Olds Aurora a/c system. I pulled a vacuum on the system for 2 hours last nite. Tried to charge it and I cant get the compressor to engage. I tried to use a jumper wire on the low pressure cycling switch but nothing.

I used a test light to make sure the clutch was getting 12 volts and it is. Im not sure where to look next. The car has automatic climate control, but when you press the A/C button on nothing is happening.

Every other a/c system ive worked on I always used a jumper wire to engage the clutch to take in the refrigerant. Maybe this car is different?

I know it has 3 pressure switches. The low pressure cycling switch, high pressure cutout switch, and one more in the back of the compressor.

Im stumped and don't know where to look next.

 

[topfuel]

Maybe the clutch coil is bad. How many wires does it have, 2?

Not sure but I believe the clutch has a constant 12v supply and is
switched on by providing a ground.

If you've got the 12v AND ground signal at the clutch and it doesn't
work, it's a faulty coil or clutch.

hth

 

[86 TR]

I forgot to mention, this is a new compressor with the clutch. Ive also checked the clutch relay and fuse and everything looks good.. When you turn the a/c on, I can hear a relay or something click under the hood but the clutch does not engage.

Also this car has a weird orifice tube. Its like a electronic solenoid!

Would a faulty high pressure switch not allow me to start the clutch by jumping the low press. cycling switch?

 

[topfuel]

Yeah a high psi switch can keep the clutch from cycling too, I believe
you would disconnect it rather than jumping it to test.

Bottom line is you need to check for the proper voltage and ground, starting
at the clutch. If it's there, you have a defective clutch. If it's not there, you
need to trace the clutch circuit until you find where the signal is lost.

How did you check the relay?

 

[liv4gnz]

make sure you test all the pressure switches backprobed as in they are plugged in and check the voltage,

check teh power to the compressor

check the ac relay

make sure there is enough r134a in the system and enough pressure in it.

 

[zues1]

i know the cadillacs you have to disconnect the battery to reset computer when they lose charge try that, mike