Now that I have an LED tell-tale so I can see when the a/c compressor is on or off, I thought I'd test the Klima relay to see if it really turned off the a/c at full throttle. To my surprise, it didn't. I'm just starting to look for the cause and wondered if anyone else has ever looked into this little-known "feature" of the car. This is on my 1995 E300D (W124, OM606NA).

All diesel (and gasoline too?) 124 models have a microswitch in the throttle linkage, connected to pin 4 of the Klima relay, to turn off the a/c compressor when the "throttle" is floored. (This is NOT the kick-down switch.) The microswitch grounds Klima pin 4 at full throttle and the a/c compressor turns off. In my case, either the switch is misadjusted or broken, something is wrong or missing in the wiring, or something is wrong with the Klima relay. Testing will tell me which, and I'll report it here, but I wondered if anyone has already "invented this wheel?"

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970