OK, one day last summer, my A/C just suddenly stopped working, all by itself.
I have never been able to either figure out, or talk to anyone that had any idea.

1). The compressor clutch and cooling fans, both of which should come on-- don't.
2). No fuse problems, either under the hood or under the dash.
3). The pressure switch is fine, but I shorted it anyway-- still nothing.
4). I'm able to get the compressor going by tripping its relay behind the pass. footwell...but the only way to get the fans to operate is by shorting the H2O sensor plug on the top of engine. But this means they're either on, or off-- no automatic operation at all.
5). I've replaced the blower switch as I thought it HAD to be the culprit. I mean, the blower has to be running for the A/C to work, right?

Does anyone know where I should go from here?

Thanks!

 

Button on dash lite up? If not button probly bad

 

Hi Tom, and thanks for the help.
Yes, the button lights up....could it still be bad? I was scanning the ETM and it has this "flow chart" of what happens when the A/C is needed:
You have the blower on, and push the snowflake button. If the pressure is right, and the evap isn't ice, then the 86 pin on both the A/C logic relay and the condenser fan relay are grounded. The A/C logic relay makes the request to the ECM for cooling, and the ECM actuates the the compressor clutch.
(I think, anyway...how the fans come into it is vague...it might be the ECM that turns those on, irrespective, of course, of overheating and high fuel temps...)
OK, so I know for a fact that the A/C logic relay is NOT getting grounded like it should, because when I do ground it, the clutch works and walla, A/C. I have the fans on anyway, so it works in this manner. I was going to just use the cruise button, which was disconnected anyway, to close the ground circuit to the A/C logic relay, but that stupid button is broken!
I will buy a new snowflake button, so to eliminate that particular variable.
It's weird: the A/C stopped working at exactly the same time my window ECU blew. I replaced that, and the A/C has never worked since.
What the hell?
Anyway, thanks again for the input!

 

Will not run when all the coolant leaks out.
Pressure switches.

Not enough freon pressure - it will not start up.
Pressure switches input to ECU I think.

 

If you got a rock into your condensor in the front and the freon leaked out - that's what happened.

or your seals are rotted.

you need to run the a/c every few weeks.
Even in the winter.
TO keep the seals moist.

 

In the 95 ETM it has a great compressor troubleshooting chart (ok/not ok) and what the fault is caused by. Tests everything A/C related, all you need is a volt/ohm meter....... Specifically I can't say what the fault is but if you lost two control boxes at once I'd think grounds or it's one heck of a coincidence. The window lift ECU is usually cold solder joints. There's a few more switches/relays involved with the A/C..... I lost a relay and that's why my A/C quit. The relay literally melted..... kind of easy to spot in my case. I had the switch light but didn't have the compressor.

 

Holy **** I didn't even think about that!! So THATS why my ac is terrible and needs to be filled at the beginning of every summer!

Thanks man I'll have to try that!