Coolant Temperature Sensor on ' 97 M104
 

Excuse me for entering this querry again, but I would like to look at the coolant sensor on my '97 E320 to satisfy myself that its wired correctly and functioning as designed. The reason for this is that my car runs better when its fully warmed up than when its cold and I assume the engine management system uses coolant temperature as a prime operating input. Somebody responded to a previous question about location by saying it's on the rear of the block. Well, I can't see it from the top. Do you have to go at it from underneath? I think there is a single wire sensor on the thermostat housing for the guage but there must be another on somewhere.

The sensor on a 1997 M104 engine should be a black square 4 pole sensor on the water pump housing.

Further Info From M.B. Doc Desired
 

Based on your reply about coolant temperature sensor location I went back under the hood last night with a flashlight. Upon removing the ornamental cover up top, all I see in the vicinity of the water pump is some type of device which appears to have a couple of electrical and a couple of vacuum line connections. One of the electrical connections is a fairly heavy guage brown ground wire. I believer there is one clear and one black vacuum line. Is this the coolant temperature sensor? Thanks in advance for any additional info.