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Corolla Air Conditioner

My son recently bought a 98 Corolla that had been driven very little for about 1 1/2 years before he bought it. After a new battery and oil change, it starts and runs fine but we found that the AC was not working and was down on freon. We refilled it and it worked fine for about a week, then quit. We figured it had a leak but found it was still full of freon. The compressor doesn't run, i.e., the clutch doesn't pull in. We checked the fuses and all seems to be fine. There may be some relays in the circuit but we're not sure how to check them.

We don't have the factory service manuals which would probably make our job easier. My question is this. What should we be looking for? What order should we be checking in?

Thanks, Harry

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SocketNews
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There's a wire that drives the compressor clutch directly (via a relay).

a) Apply +12V directly to the nearest connector. You should hear the clutch click in. If so, you could then run the engine and do the same to see if the AC starts to work.

If not, you need a new compressor clutch. More likely is one of the following.

b) the AC has a dual or triple pressure switch that disables the compressor if the refridgerant pressure is too low or high. Look for a switch device on the drier or on one of the tubes. Pop the connector and jumper it. See if the clutch kicks in. See idea of a).

c) compressors have a hi temp cutout switch too. Look for a wire, and test the switch with a meter.

d) There's going to be a relay or two that runs the AC fan and drives the compressor clutch. Look for a secondary fuse or relay box.

e) Was the AC empty or just low on refridgerant? If it was completely empty, you can't just refill it without vacuuming out the system. It might for a while, but will run hot (and eventually stop working) because the air in the system compresses more than the refridgerant.

Stewart DIBBS

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Stewart DIBBS

I like what Stewart said. My money is on b) and/or e).

Reply to
J Strickland

Thanks Stewart,

The system wasn't empty of refrigerant, just low. I'm assuming this is because it sat for so long and the refrigerant came out around the clutch seal when the lubricant crept out of the seal. So, we're liking your b). We were on the high side of the allowable pressure when we recharged, so there's a good chance we got too much refrigerant in the system. We weren't sure if there was a pressure switch that kept the system from running if the pressure was too high. I'm assuming from what you said that the pressure switch handles both low pressure and high pressure conditions through the same switch.

If that doesn't work, we'll try your a). I really don't think the clutch is out but you make it sound easy to check. It could be the relay.

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SocketNews

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