A/C Switch Light Flashes? No Cold Air!!

[geputten]

Hi all,

My wife's 1988 Celica Convert GT: Everything was a-okay until last week when she said that on the way home from work the a/c button started flashing and no cold air was coming out. She shut off the switch for a while and re-started it... yes, it started working a short time, but then the light flashed again with the same results.

Plenty of freon, and it was blowing very cold before the initial flashing of the switch....

Mentioned this to a local mechanic and he claimed it's the "revolution sensor" for the a/c clutch, but the only way to fix it is to replace the entire compressor!?! $erious $$$$$$$!!!

Anybody know of a way to bypass this sensor or just install a simple toggle switch for the clutch to kick in?

This s Tallahassee and already over 100!

Thanks!!!!

[BLUEMEANIE]

Its a 3S-FE, correct? You might be able to find a compressor at a salvage yard. Not sure how compatible they are but the 3S-FE came in several models in the mid to late 80's. Any of the better import salvage yards should have cross model/platform/maker compatibility charts.

[93celicaconv]

I think your mechanic is thinking how hard it would be for him to replace the revolution sensor, but it "can" be replaced with the compressor still connected to your AC system, because the ring is on the clutch side of the compressor, outside the compressor housing.

The flashing AC light is an indication that the compressor speed has slowed down relative to engine speed. The AC ECU interprets this to mean the belt is loose, or the compressor is turning way to hard and may be damaged by continued operation, or the clutch is slipping. Sometimes a poor retrofit from R12 to R134a will cause this problem. You may also have a clutch that is starting to go out on the compressor. You may also have a wiring problem involving the revolution sensor harness.

I would certainly check your belt tension before throwing in the towel, and check to make sure all your wiring involving the AC compressor looks good with no opens or shorts. You may want to watch your compressor when it is on to see if you notice any slippage. Just a note that, if the AC compressor has not been touched, it is very unusual for the revolution sensor itself to fail.