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Discussion Starter · #1 · (Edited)
So I'm still new here and am figuring everything out.

I have a '95 XLT and my temp gauge reads cold no matter how long I drive.
I have replaced the thermostat and it is in the correct direction and I also replaced the temperature sender.
The top radiator hose does get hot so I know that I'm getting flow through the thermostat and the radiator. I have two suspicions and I'm still learning about working on cars(engineering student so it's not my field) so that's why I'm here for help.

I read on another forum that the sender is supposed to read about 200 ohms nominally. With the new sender in the manifold it reads about 30 ohms when cold and 50 ohms when hot(I bought one from Advance Auto Parts that said it was an "exact fit"). I did the ground test suggested on other forums and in the Haynes manual. When I take the sender's lead off it reads cold like it should and when I ground it to the chassis it reads hot, however it goes to hot slowly, not instantly. When I hook up a potentiometer to the wire for the gauge and then to the chassis, there is an extremely small range for it when it goes from cold to hot. Above 10 ohms it reads cold and under 10 ohms it reads hot.
Any help would be greatly appreciated. I cant tell if I have a bad sensor out of the box, bad gauge, or bad voltage regulator. Thanks!!

Super Moderator
28,219 Posts
Yo T ,
Testing; "...Pull the R/Wh wire straight off the sender & ground it to the block, intake, or head. Then turn the key to RUN. If the needle pegs, replace the sender. If not, diagnose the circuit.
The sender should test at 74 Ohms cold; 9.7 Ohms hot. A new sender from NAPA ..." by Steve

"Coolant Temperature Gauge
Check gauge calibration as follows:
  • Using a Rotunda Instrument Gauge System Tester 014-R1063 or equivalent, with the key in the OFF position, disconnect wiring connector at the sender and connect tester to wiring connector.
  • Set the tester to 74 ohms.
  • Turn the key to RUN, and wait 60 seconds. The gauge should indicate on the COLD graduation.
  • Set the tester to 9.7 ohms and wait 60 seconds. The gauge should indicate on the HOT graduation.
  • If engine coolant temperature gauge tests within calibration, replace engine coolant temperature sender.
  • If engine coolant temperature gauge still tests out of calibration, replace coolant temperature gauge." by Ford
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