In my 560, I only have full heat all the time... even with the AC running. So, checked the monovalve insert first and there are no tears in the diaphragm that I can see. I suppose I can replace it as they are only about $45.

What are my next steps to check out? I believe the push button unit to be original to the car, is it possible it is not sending power properly to the monovalve?

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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]