A/C Compressor won't disengage
 

The A/C compressor on my 1995 E300D won't disengage--runs all the time no matter which climate control setting is used. Is this the compressor clutch failing, or a switch, or even the heater control valve causing this?

Disconnect the electrical connector to the clutch coil and see if it still runs.

Very good advice! :thumbsup2:

Have you tried to reach the compressor connector on a 606??? I'd start with something simpler like the Klima relay or low pressure switch. It's likely a bad PBU sending a constant signal to the low pressure switch, unless a 95 is that different from a 92.

Sixto
87 300D

what is a "PBU"?

Pushbutton unit. The central controller of ACC that includes the buttons you press to select functions.

Sixto
87 300D

Now the compressor won't engage..
 

Any thoughts?

First off, what did you do, if anything?

After it wouldn't disengage I unplugged the heater valve wire to see if that would have an effect, then reattached the wire. That's it.

Check the fuses. Don't just eyeball the fuses, remove each one and make sure the metal strip is intact. If they haven't been replaced in the last 10 years, replace them all. ACC blower fan might have a separate strip fuse in a small plastic box outside the main fuse box. It'll have a 30A fuse that looks just like the 80A fuse in the glow plug relay.

Sixto
87 300D