A/C compressor not kicking in. Any ideas?

[CBZGT50]

I have checked all the fuses and engine compartment fuses and relays, looked at the heat A/C switch panel and everything looks perfect. it blows hot, it defrosts, the vents work, just not the compressor. It was cold just last week.

Last weekend I rewired some of my gauges (located under the stereo) and my aftermarket radio and since then it has not blown cold. The air blows, but I can see that the compressor is not kicking on. Any body with experience to get my A/C compressor working gets a beer. Ha ha. Seriously, I have a feeling it is in the dash but what component would cause the compressor to not kick on if all the fuses are fine? I know there is something else in there that has been disconnected, pinched or cut by the plethora of wires from the stereo and gauges. I have a mach 460 system and a CD changer with FM modulator so it is full of wires behind the stereo/Gauges.


Help!

 

[tmoss]

There is a pressure switch on top of the A/C receiver on the passnger fire wall - the power for the clutch comes from that switch and if your low on freon, it won't close the switch.

 

[89 Saleen#455]

Tmoss is correct. If the system is low on freon, the compressor will not cycle. The freon carrys the mineral oil in the A/C system, so the system is designed to "shut down" via a pressure switch on top of the accumulator when the freon is low. Low freon means no oil circulating to your compressor. To see if your system is low on Freon, remove the wire harness on top of the accumulator/receiver (cylinder shaped object on the passanger side firewall), take a paper clip or jumper wire and jump both ends of the wire harness. Turn on your A/C and watch the compressor. If the compressor cycles, then the system is low on Freon. If the compressor doesn't cycle, your either have faulty wiring or a seized compressor. Do not keep the compressor running for more than 10-20 seconds with the jumper wire.

 

[JB66]

Make sure your connectors are all installed properly on the control panel. What year is your car so I can look in the proper wiring diagram?

 

[tmoss]

If you find the pressure cycle switch is passing 12v through, you may have a problem with the Wide Open Throttle (WOT) relay - mine was burned up partially and caused this problem. Here is a diagram to help you see how the power is supplied to the clutch............

 

[CBZGT50]

Make sure your connectors are all installed properly on the control panel. What year is your car so I can look in the proper wiring diagram?

I have a 95 Cobra. If you could get the diagram, that would be cool. Email to [email protected]

I checked all the connections inside but cant help but to think it is something under the dash because I was just in there a few days ago and my a/c was COLD last week. I will check on the pressure switch though. I am pretty sure the compressor is not locked up, I have had no engine problems lately. I think I will pick up a gauge to see how much pressure is in there. BTW. what is the lower pressure supposed to be?

CB

 

[87'GTstang]

Currently working on getting mine back up and running also. Mine ended up being the the cycling switch on top of the accumulator. After you get your system functioning once again, if it hasn't ran in awhile (like mine), you should really release a UV dye into the system and check for leaks - and then replace from there.