I have an interesting problem with the AC on my Honda Civic. The compressor won't come on and I think the the problem is between the switch and the relay, here's why: The coolant level appears to be OK, I've check the actual pressure and when I jump the relay, the compressor comes on. I replaced the relay, so that's new. I think this tells me that the coolant and the coolant pressure switch are functioning, the relay is functioning, and the compressor itself is OK, or it simply wouldn't come on. The little green light on the AC switch comes on, but I'm not sure that tells me the switch is working properly. I assume there's a fuse between the switch and the relay somewhere, but I can't find a reference to it. Does anyone know which fuse I should look at? Of course any other ideas would be helpful.

 

How exactly did you check the actual pressure ? There should be continuity across the ac pressure switch. Check it.

 

That's a good question holmesnmanny. Actually I'm inferring the presence of coolant from some other observations that I now realize may not be reliable. I'm going to borrow an actual pressure gauge from an auto-pars store and check the pressure directly. I'll get back with my results. Obviously if it is low on coolant, I've got a leak and I'll fix that, or have it fixed depending on what needs to replaced.

 

Why do you keep on saying coolant ? You are referring to refrigerant, right ?

 

Yes, refrigerant, not coolant. It turns out upon further inspection I had a pretty large crack in the high pressure line, right next to the fitting to the condenser. I couldn't see it even with leak detector until I got the the plastic cover in the engine compartment off. I looked down at the line with my black light and there it was. So to answer a question... I was wrong, there was NO refrigerant in the system at all. I replaced the line and had the dealer recharge the system... no leaks, and she's cooling like a champ now.