Hi,

Thought I'd start off with a new question:

I'd like to know what all of the sensors are for that I see on the sensing chamber of my 1991 190E 2.3.

1) A two-pole sensor with a single plug.

2) A sensor that seems to be covered by a boot that almost looks like a spark plug wire.

3) A sensor that has three poles. There are two plugs that connect to this sensor.

4) A sensor that appears to be attached to the side of the water pump.

Thanks,
Sleepdoc38

 

I know 1/2 of no3 -- the plug with 2 pins is for rad fan clutch .yoo can short this out in emergencies if your rad fan wont work in hot weather.

 

Hi,

This is most helpful. I seem to be fairly certain that the sensor with just 2 poles is for the electric fan.

Now on #3, the sensor with 3 poles, I seem to think that the single-pole plug goes to the temp guage on the instrument cluster. But I never knew what the other two poles were for. If this is the fan clutch, then I may have figured out my problem as my fan clutch does not engage at hi temps - only when the A/C is on. How do I short it out to test it though?

Thanks again!!

 

hi just get a short piece of reasonably heavy cable take about 10 mm of insulation at both ends and double it back over insulation ,then put wire in holes .this is only as a test for you fan really . if you were going to leave it like that for any length of time i would put bullet connectors on wire & insulate it .then tie out of the way

 

Sounds good. I'll try it tonight. It's nice to know that my clutch does work when the A/C is on. So at least it's just a wiring problem somewhere between the sensor and the clutch itself. If I hear that wonderful sound tonight when I jump the poles, I'll know to get a new switch.

Thanks!!