Need help troubleshooting AC

[b_nadenbousch]

I have a 1995 K1500 5.7L. The AC is fully charged and I had a new evaporator, tube and compressor installed last spring. Now the compressor clutch doesn't engage. I jumped the plug from the evaporator-clutch didn't engage. I took both plugs from compressor and didn't have voltage. Please help.

[2000CAYukon]

Next step is to look at the relay. The PCM commands the compressor on via the relay. If the relay is bad, it may not be allowing the power to flow to the compressor.

//2000CAYukon

[2000CAYukon]

Forgot to add that the power source for the relay is also fused so you need to check that fuse as well.

//2000CAYukon

[b_nadenbousch]

I changed the relay with another relay of the same number and checked the fuses. No change.

[2000CAYukon]

Originally Posted by b_nadenbousch

I changed the relay with another relay of the same number and checked the fuses. No change.

OK. You still need to verify that you have power to relay. You can also ground the PCM signal to the relay to force power thru the relay.

If things work when you ground the PCM signal to the relay, then the problem is either the PCM or the AC controller not telling the PCM to turn on the AC.

//2000CAYukon

[MT-2500]

Originally Posted by b_nadenbousch

I changed the relay with another relay of the same number and checked the fuses. No change.

Like said make sure your relay is switching and has power.
On this one the high side pressure switch is between the relay and the compresser.
Time for a good wiring diagram. if you do not have one e mail me at [email protected] and i will try to e mail you a pdf on the wiring.
MT

[Mr. Smith]

I hate to state the obvious but are you sure there is still freon in the system? I know you had is serviced a year ago but leaks do happen. And if there is no freon...no workey.

[v10_viper]

Was having the same problems with my '92 just last night, disconnected the battery because i was playing with wires, I don't think I fixed anything but once I connected the battery back up and started the truck it worked, and blows out 39.2º cold air, so I decided to return the kit to walmart, save 20 bucks.

So you can try to just unplug your battery, but like I said, I'm not sure if that's what it was or not.

[fordin K]

maybe it is your cycling switch that is bad and not causing the comp. to engage, idle to up and cond. fan to kick in. if every thing else works an the comp. still doesn't, i would say control circuit to clutch maybe.