1979 240D Engine Temp Coolant Gauge Sensor
 

I need to change the sensor out on my 240 D. One is the glow circuit sensor the other is the temp gauge sensor

Which is which. I think the temp sensor is the one further aft closer to the firewall.

Tried disconneting the electric connection on both while car was running but the gauge did not shut down or move off when either electrical connection was removed.

Please let me know which one it is. Thanks Tom

If you pull one wire off and check the gauge and its not affected its the other one. (Have the car warm so its showing something)
as I remember the other one is for the glow plug relay, you should be able to figure it out