Hi,

I recently had to replace the compressor clutch relay on my '94 Accord, because it was missing when I got the car. This didn't help the problem, so I found a very big .pdf manual that had a flowchart. First, I have confirmed that is a problem with getting the compressor to come on, and not a problem with any part of the climate control. I have confirmed that the new relay is good, that all the fuses are good, and even jumpered and checked voltages into the clutch connector; voltages are good and the compressor clicked on. The next step was to hook a test harness to the main harness and check voltages. What test harness are they talking about? There is a picture of a harness but I don't know what it is for. Is this meaning I have to go out and buy some extra thing just to troubleshoot?

We ended up also wondering if the low pressure switch was being activated. I didn't want to remove the battery and tray to get to it (and where I was I couldn't get under the car), and so we evacuated the system to be sure, then jumpered the clutch connector to get the compressor to come on. It did and we filled it up and it got quite cool inside. But then we removed the jumper and the compressor stopped. Is it common for these pressure switches to just go bad?

My last step after the test harness thing, once I figure it out, is to replace with a known good ECM if I have voltage, or fix a diode thing if I don't have voltage. This isn't going to very easy for me since I don't have these parts just lying around, and I'm a college kid so I can't afford any anyway, regarding the ECM. But is the ECM going to really be a problem if all my other engine functions are running great?

Thanks for any and all help...

so with it charged up, jumping the low pressure switch made it work? is that the bottom line?

if you have no money, why don't you just wire up a switch to manually turn on the compressor if that's all it needs. if the fans work, etc.....

I'd prefer to not have to work to get wiring through the firewall if I can get it to work right. Plus since most compressors cycle, I don't want to have to worry about doing that myself.

anything under that battery, especially if it's had a cheap leaky battery in it could have corroded to the point that the switch or harness is damaged.

If you can get to the plug for the switch, unplug it and jump the terminals to see if the compressor will engage.

Do you have power to the relay hot AND trigger pins? Also, check to see by jumping the hot supply and output pins with a jumper, does the clutch engage? Then, while everything is on, with the relay out, is there ground at the relay's trigger pin?

Do the fan(s) come on when you push the a/c button?

It should be fairy simple to diagnose, you should also have somewhere in the system a high pressure cutoff switch, more than likely in the line to the drier or on the drier itself. Based on other setups they are normally closed, and if the high side pressure goes too far it opens to kill the compressor as to not damage anything.