Hello, thanks again for all of the suggestions and help. The dealer called back and it ended up being the ECM being faulty. Their price for the ECM alone is over $500, so I am ordering one from Ebay for $100 and going to attempt it myself. Does anyone know if I will have to reprogram my keys or do anything else once I install the ECM when I get it? Thinking back, last fall my voltage regulator went out, which fried my battery. When this happened, I was getting 17.5 volts across my entire electrical system and I'll bet this fried the ECM. With the money in gas this car saves us, I'm happy to invest some money to keep it going!
Matt

 

I have the same problem with my 2002 honda civic. I need to get my ECM replaced. Can you tell me how was ur experiance. did it work from ebay. Did you you need to get ur car to the dealer for reprogramming.

 

i have civic 2002 with 85000 miles. the ac stops working . it has freon in it . and i check all the fuses all good ,relays also all good. compressor relay it doesn't have ground on it whenever i ground it it well come on . also the wire blue / white going to compressor its doesn't have any power whenever i jump it with ground every thing work fine my question is why i don't have ground in the wire?"

 

i have civic 2002 with 85000 miles. the ac stops working . it has freon in it . and i check all the fuses all good ,relays also all good. compressor relay it doesn't have ground on it whenever i ground it it well come on . also the wire blue / white going to compressor its doesn't have any power whenever i jump it with ground every thing work fine my question is why i don't have ground in the wire?"

 

Check the pressure switch (on the receiver-drier) and the thermal switch on the compressor for continuity. Both should be closed in normal operation. Does the condenser fan come on when you try to engage the A/C? Does the engine idle speed increase?

The control circuit is pretty much all negative logic (when wires are pulled to ground, the compressor starts). I think the control panel grounds the wire to the condenser fan relay, starting the fan. Then if the pressure and temperature are OK the ground passes through those switches to the ECU (via the Multiplex Control Unit). The ECU gives the engine some extra gas and air and after about a 1/2 second delay,grounds the compressor relay.

 

thanks
also i dont have any power at all on the pressure unit why ? from where the wire come from ?

thanks

 

I think it comes from the thermal switch, would have to pull the diagram to be sure (find one of Ron J's posts and follow the link in his signature). Is the thermal switch OK (closed circuit)? A lot of them have gone bad.

 

The ECU provides ground to the compressor clutch relay on the Red wire. Check this wire and the ECU connection.

 

do you mean the red wire go from ecu to the compressor ! in my case its blu/red and no power at all on it . ( i dont have any ground on the pressure swich ) so it could be the ecm ? or thermal swich ? thanks

can you send me please an a/c adigram for 02 if you have.

thanks alot.

 

A relay has two sides. Power supplied on one side serves to activate a switch on the other side. The red wire is the activator side of the relay that turns on the switch on the other side, which then can send power through the Blu/Red wire to the compressor clutch. The red wire is grounded by the ECU. If this gound is not supplied, the compressor clutch won't get power.