I recently replaced my temperature switch/sensor to find out I still had the same problem, gauge moves slightly. I used a jumper wire to ground the connector and the gauge needle moved all the way over to the hot side. This tells me the gauge is working properly or so I think. This is on a 22 RE 1994 pickup. Any thoughts or ideas?

 

I have a similar issue, if I wiggle the wire the sender works again. After a few minutes from the engine running the vibration must wiggle it unconnected again.
You replaced the sensor or the sender? I have only replaced the sensor because that was bad.
My guess is your wire has a short some where.I've noticed on my truck( from Florida originally) that lots of plastic is brittle and some wires have cracked jackets and corrosion where the jackets have cracked to the point that some wire have lost continuity. I've repair the ones I have found except for the temp gauge.

 

I am calling the Switch and the sensor the same thing (located by the intake with one connection). I will try the wire, to check for any short or bad connection. don't think this is the problem though, as I have jumped the connection to a good ground and watched the gauge move. It is baffling me so far.

 

Sender has one wire, and the sensor has two. Have you put a multimeter on the sender to check resistance?

 

Haven't checked the switch yet for resistence. Hopefully, I will soon. Just don't can't figure why the gauge will move when grounded and both switches I have put in have not go a t reading.