My 95 E300 Diesel AC Compressor is acting-up. When I turn it on it engages for less then 1 Second and then shuts-off, never to come on again unless I turn off the engine and restart the car. It then comes on again for 1 second and shuts -off.

I suspect that the problem is speed sensor related but am not sure how to properly diagnose it.

I assume the cause could be any of the following:

1) Defective AC Speed sensor
2) Slipping drive belt (Does not appear to slip)
3) Slipping AC Clutch (Does not appear to slip)
4) Defective engine speed sensor.

How can I tell which one of the above possibilities is the actual cause? Is there a way to bypass the AC speed sensor? At least for diagnostic purpuses.

BTW, Freon is at the right capacity, and when I apply power directly to the compressor, it does come on, stays on, and does cool the car properly.

HELP

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]