Hello everybody,
This past July 4th I bought my first cummins (I'm coming from the mustang world here) and have since been working on it trying to get it road ready. The truck is a 93 4x4 5-speed cummins first gen BUT it has a 94 P-pump 12V motor so I figured it would make more sense to post in this section. Now that we have an idea on the type of truck, the question....

From what I can see the coolant temperature gauge on the dash is not operating, so I figured I would start the problem search with the coolant temperature sensor itself. After some searching here on DTR I found that it is supposed to be located on the back portion of the head on the driver's side. When I went to look for the sensor, I didnt find just one...I found two!!!

Here are some pics of the motor/sensors:


And a few of some grounds around the battery:

(Read that some of these grounds are directly correlated to dash gauges?)

So if somebody can enlighten me on which one of these two sensors is the real coolant temperature sensor and as to what the hell the other one is it would be much appreciated! Also if anybody has any suggestions on getting the gauge working again that would be much appreciated as well. Thanks,
--Garrett

 

Neither of the two sensors shown is for coolant temperature. The one that's plugged in is the intake air temperature sensor, the larger one looks like the KSB air temperature sensor that the original VE injector pump would have used. The sensor you are looking for doesn't point up on the top of the engine, actually it's on the side of the head, way at the back behind the fuel filter.
And welcome to the site!

 

For some reason the connector for the coolant sensor becomes unplugged easily.
Could be your only problem.

 

Thanks for help fellas!

Found the sensor, it was plugged in and everything. I finally got around to putting in, filling up, and firing the truck up last night with the new radiator. Once the system had coolant in it plus the radiator and hoses connected the coolant temp gauge actually started to work.