My 97 4.0 5 speed XLT has an issue either with the temp gauge or cooling system: replaced thermostat and both temp sensors: temp gauge still doesn’t read above 1st mark-same as before changing out the above: any thoughts/suggestions?!!
Thanks!
Judgejohnmd

 

Yes, temp gauge should show just below 1/2 after 5 to 8minutes of driving
1/2 is 200degF on gauge
Engine should run at 185-195degF
Thermostat should be 190-195degF model

Only one temp sensor(5volt), the other is a temp sender(12volts)

The one with the red/white wire is the 12volt sender, it may or may not have a black/white 2nd wire in 1997(this 2nd wire is a ground wire and should be tested)

In any case remove connector from sender, use a jumper wire from red/white wire to battery negative, or any metal on engine, a ground
Turn on the key
Temp gauge should go up to HOT, if so gauge and wire are OK, if not then gauge or wire is the issue

If you have a 2nd wire then jumper the red/white and black/white wires together and re-test, gauge should go to HOT again, if not the black/white wire is not a good ground

If gauge goes up to HOT then replace sender, new or not, and do NOT use tape on lower threads of sender, it needs a good ground to engine

I assume your heater does not get very warm
That would confirm and over cooling issue not a sender/gauge issue

If heater gets HOT then its a sender/gauge issue

 

I do get good heat, after replacing blower which was full of mouse house crap: I’ll do the ground checks tomorrow & post results.
Thanks!!
John