The temperature gauge in my 2001 Ram 1500 started fluctuating at rimes and would run at normal temp other times. I replaced the temp sensor but the pigtail/socket came apart when I took it off the old sensor. I put the socket back together and plugged it into the sensor. Now, the temp just reads over to the right. I've changed the sensor and still the same thing. I would suspect that the socket is just bad but a mechanic friend looked at it and thinks the socket is still good and attaching fine. I also performed a gauge test and the temp gauge calibrated like the rest of the gauges.

 

I would suspect the socket or just a crappy temperature sensor.

 

Thanks! I forgot to add that I thought the sensor might be bad so I tried another new sensor with the same results. I've bought a new socket so I'll try to wire that in and see if that works.

 

These trucks hate aftermarket sensors. Especially BWD

 

That's what the parts house had, of course! Do I need to try a sensor from Dodge?

Well, the first one was BWD. The second was from NAPA. Im not sure of the brand on that one.

 

You could. What I would do is replace the connector and see if it changes. If it doesn't then I would try and find the MoPar sensor online as it will be cheaper

 

Needle all the way to the right is very low resistance, possibly a short to ground. Disconnect the sensor and see if the gauge changes. If it doesn't it's probably not the sensor but the wiring. You can also check the sensor with an ohmmeter.