w123 Cold engine lockout switch/temp sensor
 

Hello, I'm wondering if anyone can resolve a point of confusion regarding the temperature sensor on my car, an '85 300TDT (federal) w/ 88K.

Is the sensor at the thermostat housing, the "cold engine lock out" one a different part than the sensor on the left side of the block that communicates with the gauge in the instrument display?

If so might anyone have link to the part number?

Thanks!

Here is a picture of the part, the thing is I don't see mention of this part anyplace else. https://ppembzparts.com/i-30504503-mercedes-cold-engine-lock-out-switch-1981-1985.html

Lock outs are normally on off contacts. The sensor for the gauge is a resistance to temperature change.

It’s a temperature switch. It goes to the hvac controller to make sure you don’t get a blast of cold air in your face when you start your car. Locks out the fan till your engine heats up. Check function with a meter. It shorts to ground.

Don’t know the pn. Check with your dealer.

If you can live with the threat of a little cold air on a cold day, just terminate the switch wire to ground (permanently) and be done with it.

Just some follow up. I bit the bullet and got a new switch (took a few weeks, it came from Germany) Unfortunately, no change in the function of the ACC, it still does not lock out until the the coolant temp gets to be over 40C. The puzzle continues.