Remove four screws and inspect the monovalve diaphragm. Do this before wasting any other effort. If it checks out, then check for voltage at the two pin plug.

86+ climate systems are far more simple than the 85 and older in the W126. PBUs are not a big failure point on these in my experience.

Do you not have the W126 service discs? It shows how to repair everything on these vehicles. You need to be able to use a multimeter and understand basic schematics.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]