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Re: 91 Civic AC Wiring

I'm trying to figure out why the AC compressor on a 91 Civic isn't

> engaging. There's plenty of freon and the compressor kicks on if I > apply 12V directly. I've followed a diagnostic chart from an Alldata > disc, and it appears the ECU isn't activating the relay. I'm dubious > however that the ECU is the problem. > > I don't have the shop manual or wiring diagram, and the Alldata disc > makes no mention of the AC switch on the dashboard. How do I test if > the dash switch is telling the ECU to turn on the compressor? The blue > light turns on when the switch is depressed. I know the kids were > messing around in that area recently to install an aux wire onto the > back of the aftermarket stereo. > > Can anyone describe how that part of the system works, and perhaps a > pin on the ECU to check for 12V or ground with dash switch on/off?? > > -RC

If, as you say "the kids were messing around in that area recently to install an aux wire...", the first thing to do is check ALL the fuses under the dash and under the hood to see which one they blew. Then pull the radio and trace all the wires that were messed with and see where they tapped into the wrong one. You will need a wiring diagram for this. You should be able to find the service manual/wiring diagrams on line somewhere. Start with

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Reply to
E. Meyer
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If you have Alldata, all the necessary wiring diagrams are there, along with ground locations and trouble trees. It's also helpful if you have some experience in this kind of troubleshooting.

Reply to
Ed

First, a response to earlier messages-

1) I repeat, there's plenty of freon. I hooked up my gauges and pressures are normal. That's the first thing I did. Compressor was replaced by me about 1 year ago with a unit from Arizona Air, along with receiver and expansion valve. Recharged with R12. 2) I checked the fuses. They're fine. The relay is getting 12V on both the hot wires. That's part of the Alldata troubleshooting. It isn't seeing ground from the ECU.

Back to the Alldata discs. I bought these back when the car was nearly brand new (early 90s). I've dug around and can not find comprehensive wiring diagrams on the disc.

I'll check again.

-RC

Reply to
RC

Followup. I found the wiring diagrams on the Alldata discs. I have plenty of experience with this kind of thing. I'll try to report back what the problem is. :-)

-RC

Reply to
RC

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