Hello all. Just recently bought a 1998 Honda Accord, 4 cyl, auto. The a/c clutch is not engaging when I turn the air on. Pressures are good no apparent leaks. I can ground one side of the switch on the drier and the clutch engages and the ac blows ice cold. Is this a faulty pressure switch or something else ? Any help will be greatly appreciated. Thanks

 

Start at the pressure switch and work backwards to see where the ground is missing. The order (if I remember correctly) is pressure switch, a/c thermostat, a/c switch (in the car), fan speed switch, then ground.

See if there is continuity between the leads on the pressure switch. There should be continuity. See if you have continuity to ground on the ground wire at the pressure switch connector when you have the a/c turned on in the car.

 

Thanks for the info. I forgot to include in my description, system was low on freon, charged system, clutch engaged and cycled properly(this was yesterday). Drove vehicle home from work 30 miles, ac worked great. Today on the way home no clutch engagement. only way to engage is grounding switch.

 

If you are losing pressure that quickly, you have a leak somewhere.

You can get freon that has a dye in it. Add some to the system, then look for leaks using a UV light.

You can also look for dirt/oil buildup on any of the threaded connections in the system, because the R134a evaporates immediately.

The shaft seal on the compressor can leak. Also there can be leaks in the evaporator box under the dash.

IMO, if you are going to discharge the system to fix a leak, I would replace the o-rings, receiver/drier, the expansion valve, and possibly the shaft seal. I just think that doing the job right the first time will help ensure that you don't have to tear apart the system for a long time. We can give you more detailed info on doing this once you determine the source of the leak.