I have 92 300SL. The clutch on the A/C compressor suddendly stopped
engaging. The compressor freewheels. Air was cold until this happened. I
checked the fuse and it is OK. Any ideas what to check next? If it's the
You can jumper the low pressure cut-out switch and test the compressor
clutch to be certain your problem is low freon. Since the car is a '92, low
freon is the likely problem. Hopefully you can just add a pound every summer
and that will get you by.
CAVEAT!!! I am only familiar with my '86 420SEL so don't bank on what I tell
Facing the front of the car, hood up, look to the right front side of the
engine compartment, a little behind the radiator and to the right of the
radiator. You should see the receiver/dryer "bottle" with a small circular
piece of glass in the top (sight glass). Somewhere, very close if not
attached to the bottle, will be a switch with electrical leads connected via
a plug. Unplug the plug creating its two halves. Take a piece of 12 gauge
single strand copper wire, like household romex, and make a "U" shaped
jumper. Now, holding the plug half that's NOT FROM THE SWITCH, insert each
side of the U into the two female recepticals of the plug. You should now be
simulating a closed pressure switch signaling adequate freon pressure.
Therefore, the clutch should engage. You do this at your own risk as I am
not a mechanic but only a mechanical engineer.
Before attacking the A/C clutch you ought to ensure it's getting power.
There are usually some safety block outs to protect the compressor - low
refrigerant being the one I'd first check of jump for brief test purpose
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