marlinspike

Leaving for work at 6:30am and getting back at 6:45pm sucks. I guess this is one for the weekend.

Laserjock

Before running wires and alligator clips, just perform the test with the AC button in and then out. Does 2 things, test the AC button and the relay.

Looking a bit above the relay in the diagram, if your system pressure is low, the pressure sw wont allow the AC comp to engage. Have you put a gauge in the system?

3 and 4 is a Normally Open contact. Set your meter to beep when the coil is energaged

Fabrik8

That should be 3 and 1. Term 4 is one of the coil terminals.

ILLEGAL

faster test if you dont have the tools to do the job, is pop in a new relay....

Laserjock

typing wiuth gloves and number keys don't mix :you're right, i meant 3 and 1

is energaged a word? lol

marlinspike

I haven't checked the pressure, but it was cooling strong right before it stopped working at all. That and I tried jumping the pressure switch, and it still didn't turn on the A/C.

I have a bunch of relays, but they don't have the time delay. Can I just stick one of them in for the purpose of the test?

Fabrik8

You can use another relay for testing if you want. The time delay is usually to add hysteresis or to keep a control loop from latching into a particular state, so without the right relay the system may not turn on and off exactly the right way... A regular relay should be able to tell you enough to know if the time delay relay is bad though.

marlinspike

Cool, I'll just borrow the wiper relay.

marlinspike

Ok, so it's not the relay. And it's not the low pressure switch. I doubt it's the pushbutton unit because that has 3 buttons that each call the A/C into action, and none of them will turn on the compressor. That and if you somehow make the unit so no buttons are pushed it defaults to compressor on, and that isn't turning on the compressor either.

Anybody have any other ideas? Here is the full diagram.

BAD4DR

Yes - Take the connector off the clutch assembly. Measure the voltage across there. See if it is turning on.
If yes, then clutch assembly is problem.
If no -
Measure ground side to battery positive and negative with ohmeter. (Key Off) Should have no short to battery positive, and little or no resistance to ground.
Do the same with the power wire, should definitely not have any continuity with ground.

Make sure both fuses shown in the diagram are good.
If there's any doubt it's the control side, verify you have power at relay pin 30. Measure it to battery ground.
If you have power at pin 30, put a jumper wire between 30 and 87. This will energize the clutch. Should work at that point.
If no, then fix power feed issue to pin 30.
If yes - you need to check pins 85 and 86, and ensure they are energizing.

Please note - Make sure you have a mechanical fan, or that your electric fan is working. If the electric fan is not working, you will have no A/C at idle and/or low speeds.

Need any additional help, PM me for a phone #.