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850 AC still kinda sucks :P

My air conditioner works occasionally.

After some research on the net, I decided to bypass the "superheat" switch and recharge the system.

Now, it blows cold but seems to stop now and then - almost like when the "superheat" switch was still installed - only now the pauses in the generation of cold air aren't as frequent as when the switch was present.

They also seem to occur only after the A/C has been on for a while (10 minutes+). Shutting the *whole car* off for about 5 minutes will let it start again - shutting off *only* the A/C for a bit doesn't seem to help at all.

Just to confirm, the "superheat" switch was the white connector running from the compressor to the car's wiring chassis. I've cut out that switch and joined those wires directly. The black wires, I've been told, are a diode - something to protect the radio reception and aren't related to this problem.

I suspect maybe it kicks off due to low pressure but I don't want to overfill the system for fear of popping something. The gauge/valve setup I have shows the level to now be acceptable with the car running, A/C on and compressor on.

Ideas?

TIA, John in NH ~~~ The biggest obstacle on the path to success is the stupidity of others.

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John in NH
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Sounds to me like low refrigerant, easy enough to check though, just measure the voltage across the pressostat, it should be 0 with the system operating correctly, though when the switch opens up you'll get somewhere around 12v across the open switch.

Reply to
James Sweet

I'll do that - if you can tell me where the pressostat is! ;)

BTW, is this James from RGVAC?

~~~ The biggest obstacle on the path to success is the stupidity of others.

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John in NH

Another problem is that the A/C works fine for a while - typically 30 minutes or more - then cuts out and doesn't work until the car has cooled off. This is usually caused by the gap in the compressor clutch being too large, and the magnetic force is not enough to engage the clutch. (Removing the superheat switch from the circuit as described above will help this problem, as it will increase the voltage available to the clutch a small amount.) Others have used the wire going to the clutch to engage a relay that is fed power directly from the battery.

Reply to
Mike F

I'm willing to give that a go at this point - where would I run the wire TO - from the 12v on the battery directly to the former superheat switch wire that goes into the clutch - bypassing the wire from the car's wiring chassis alltogether?

TIA, John in NH

~~~ The biggest obstacle on the path to success is the stupidity of others.

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John in NH

It would be like wiring a relay into your headlights, and for the same reason. You need a standard 4 or 5 pin relay. Run a fused lead directly from a power source (always on) to terminal 30. Run a wire from terminal 87 to the connection at the compressor clutch. Connect the wire that was on the clutch to terminal 86, and ground terminal 85. If the relay has a fifth terminal, it won't be used. Make sure there's a fuse between the power source and your relay! Use fairly heavy wire to minimize any voltage drop, and try to run your wires along existing harnesses to keep them out of the way of heat and moving parts.

Reply to
Mike F

Great - I've got a J relay and seems like that would do the trick!

As soon as the rain lets up, I'll give it a go. Thanx! ~~~ The biggest obstacle on the path to success is the stupidity of others.

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John in NH

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