Temperature gauge stopped working after replacing the coolant temperature sensor

  • 2000 FORD F-350
  • 7.3L
  • V8
  • 4WD
  • 200,000 MILES
My temperature gauge worked fine. Accidentally broke the sensor so I replaced it. Now temperature gauge won't work.
Do you
have the same problem?
Thursday, December 17th, 2020 AT 6:03 AM

1 Reply

I can only find reference to a single sensor for your engine. It's a two-wire design that is used for the Engine Computer and the dash gauge. In this case, it only feeds the instrument cluster. From there, digital signals are sent between it and the other computers.

This first diagram is for the coolant temperature sensor as it relates to the instrument cluster. The second one is for the same sensor as it relates to the Engine Computer. As you can see, they're the same circuit, # 39, and the same sensor.

Besides the sensor, what is the condition of the connector? If either female terminal has spread, it may not make good contact with its mate in the sensor. A quick way to check the rest of the circuit is to ground the red/white wire at the sensor. You can do that by back-probing through the rubber seal, next to that wire, with a stretched-out paper clip, then use a small jumper wire between it and the engine. That should make the dash gauge read full-hot. If it doesn't, there's a break in that red/white wire. You can also unplug the connector, then touch the paper clip to that end of the terminal for the red/white wire. If you do it that way, be careful as the paper clip is fatter than the hole in the terminal, and that can also spread that terminal to the point is doesn't make good contact.

If the gauge does go to "hot" when you ground the red/white wire, there has to be a break in the yellow/red ground wire, a bad contact between the terminals in the connector, or it's the wrong sensor for the application.
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Thursday, December 17th, 2020 AT 12:48 PM

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