I have a 1994 Honda Civic and when I bought it the ac "didn't work". I found out that the condenser fan fuse was blown so I put another fuse in it (a 30 instead of a 20) and it worked fine until one day I was sitting in a parking lot and suddenly it was putting the engine under a lot of load and the ac turned off on its own. Now it won't come on unless you ground one of the wires from the pressure switch. I am not sure what that means so I'm just trying to determine why it's not working without grounding that.

When that wire is grounded, the pump and fan both run. When it's not, neither do. I am sure it has enough freon. I charged it and a shop checked it. I replaced the pressure switch with no luck. Any ideas? Shop says it may be the computer but I don't want to go hunting for a computer in the junk yard until I'm sure.

Any help is appreciated. Thanks guys.

 

Basic concept - Do not install higher than recommended amperage rated fuses. It's a fire and burn up the wiring risk.

It's not a bad ECU. Keep your car away from that shop.

Take your car to a REPUTABLE shop that specializes in A/C so that they can performance test it. You may have overcharged the system with refrigerant.

 

They did say that they think it's supplying improper voltage. But I tend not to believe them. I am fairly certain it has the proper charge. It's been charged by two different professional service machines during the diagnostics I've already done. Any hints as to trouble shooting this? I'm not completely incompetent but with my basic knowledge of air conditioning and no idea about what might be wrong I assumed a shop was my only option. But in reality it was just a waste of 100 dollars that I could've spent on what it needs. I cannot figure out why with a proper charge and a good pressure switch it wouldn't work. The lights on the dash work for the ac switch but even the fan doesn't come on now with that button pressed and one thing I remember about my old civic before this one is that the fan always ran even if the pump didn't come on. So that caught me off guard

 

Does the AC work at night or in cooler weather? My AC used to not work during hot days when I needed it most. My problem was a faulty AC switch. I replaced the whole HVAC control unit and it's been fine since, though it's probably only a temp fix as the wiring harness connector to the HVAC control is black (as in it was hot enough to burn the plastic connector). At night or in cooler weather my AC would work with the faulty switch.