I have a -96 F250 4x4 Powerstroke. Recently, the temperature gauge simply died - well, sort of.
This is what's happening:
1: When the ignition is turned on, the gauge travels LEFT (well below C-mark)and stays there.
2: Even after the engine warms up (which takes a while with the powersmoke) the gauge does not move from this position.
3: When the ignition is turned off, the gauge slowly returns to the C-mark (ie: travels RIGHT.)

I removed the sensor unit from the thermostat housing (and flooded the driveway with coolant...) and stuck it alternately in hot and cold water. There was a change in resistance, measured with an antique analog ohm-meter, from about 1K Ohm to 6 K Ohm.
I also shorted the red/wht sensor wire to ground, and there was NO change in the gauge reading.

A dealer quoted "about $20.00 for a new sensor, $170.00 for a new gauge, plus labour." Ouch. Before I spend any money on this, I would like to see if anyone else has had similar problems, and what has solved the problem. I did peruse the archive, and found some temp gauge related problems, however none similar to mine.

Thanks in advance!

 

You need a test light or (preferrably) a test meter (DVM). Make sure you have the correct temp sensor,, don't know about powerstrokes, but the gas engines, with fuel injection, have a temp sensor for the gauge and AT LEAST one more for the engine management system.

Generally, the sending unit for the gauge only has 1 wire going to it... can't find what color wire is used on the deisel in my manual. Unplug it and stick your test light or meter's probe in the plug and ground the other side. Turn on the key and see if you've got about 12 - 14 vdc.

If you've got power then you need to turn off the key and jumper your sending unit's plug to a good ground. Get in, turn on the key for only a couple of seconds!!! Your temp gauge should peg above "hot". If it does, you don't have a problem with the gauge. If you leave the key on for any length of time, with the plug grounded, you'll fry the gauge!

So if the gauge pegged when grounded, you gotta look to the sending unit. Pull it, clean off the threads and use Teflon tape to seal it.. don't use RTV or anything else. The sending unit needs to ground through the threads. If that didn't help, then get a new sending unit... NOT EXPENSIVE at Auto Zone or Pep Boys, etc...

If you've isolated it to the gauge, it's not hard to pull the instrument panel apart. Maybe it's not seated properly. Go to a junk yard and buy a gauge for $15. Pop it in and you should be in business.