Why not change the ($10) cabin temperature sensor?

Silly thought here. After changing out the monovalve (both the kit and the whole shebang) on my '86 W126, I still had heat problems, as well as the blower motor blowing at random. I changed the $10 temperature sensor, which is located in the dome light assembly. Remove the assembly as if you were changing the bulb and you'll see a plastic elbow at the end of a thick rubber tube. Detach it from the assembly and tube, put the new one in place, and you're done. Just be careful of the brittle plastic!

I also did this to my uncle-in-law's '87 420SEL. Since this simple repair, our climate controls have worked liked champs!

- Casey

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Casey Cooper
"From a long line of Mercedes ownership"

'86 300SDL 250K miles (Gone, but not forgotten); best diesel I have ever driven, too bad about the Achilles heel.

'81 240D 370K miles (Sold to my brother after 9 years and 150K miles of reliable driving!)

[Five other Mercedes in family clipped for less length.]