How many different 'coolant' temp gauges on my car - '91 300CE
 

I have two sensors on the thermostat housing - one 2 pin gauge and one 1 pin gauge that goes to the instrument cluster. Do I have a 4 pin one somewhere? Online parts catalogs show one, but I can't find it anywhere?

This is the M104 motor...thanks.

ryan

I think I found it. It is not located on the cylinder head anywhere but connected to the thermostat housing just like the other 2 sensors. It is connected kind of parallel to the ground at the right side (looking from the front of the car) of the thermostat housing. I just can't figure out how to remove it for sure. I guess you just pull it straight off, but it's on pretty tight...

ryan

Gotta pic? I have the same engine as you in my 92 coupe.

you should only have 2 coolant temp sensors (i think). the 2 pin one reads the temperature for the CIS system and reads the temperature for the auxiliary fans. the 1 pin is for the instrument cluster.

what's going on with the car that's making you look for the sensors?

Isn't there a temp sensor located at the rear of the cylinder head along side the valve cover on the driver's side, uses a very thin wall 22 mm socket to remove, early ones are two connections and later ones have a four connections?

I am tracking down a slightly rough idle problem and intermittent warm start issue - nothing major. I cleaned the idle control valve tonight and was just trying to check the sensors.

I don't have a pic - but I'll try to post one tomorrow.

I do not see one anywhere near the rear of the engine - and I finally located the correct FSM picture showing one at the thermostat housing - at least I think I did. I haven't pulled off the connection yet - really tight.

ryan