My Coolant Temperature gauge on the dash does not work. The indicator needle stays at 210 whether the ignition switch is on or off. It does not move.

I have changed out the Coolant Temperature Sensor on the rear of the head (O'Reilly Auto Parts # WT430) and the contacts appear to be good. Be advised it is NOT the same sensor as the Fan sensor at the thermostat housing. See pictures.

Any suggestions on how to test the dashboard gauge? Are replacements available?

1996 XJ 4.0




Coolant Temperature Sensor-Gauge (O'Reilly Auto Parts #WT430 )





#WT430 Single pin connector - 15 mm deep socket





Coolant Temperature Sensor-FAN (AutoZone Part# 195750-SU3035)





#195750-SU3035 Two-pin connector

 

Not sure about your area, but they're dirt cheap for a single gauge in the junkyard here.

Is that what it did before you replaced the sensor?

 

if im not mistaken that is your temp sensor which tells your ecm not your gauge. You have a smaller sensor on the back driver side of your cylinder head which sends the signal to the gauge.correct me if im wrong. i was wanting to hook a auxiliary gauge up and thats what i was told you have to use. here is a picture. so something between there and the gauge itself is probably the issue

 

Changed out both sensors (front and rear of head)
Cleaned connectors.
Tried grounding pins-key on- no needle movement.
Gauge has not moved prior to and after these steps.

Looks like it is the gauge. Any links out there for dash removal / gauge removal?

 

It's pretty straightforward, here's a vid from BleepinJeep... The gauge overlay bit is irrelevant but the first part is a good how-to for removing your cluster. Also, your '96 will be identical to what's in the video.


Once you have the cluster out and the front covers off, the individual gauges unscrew from the back.

Good luck!

 

Before you tear apart the dash, make sure the sender they gave you is the correct one. There is one for the dummy light dash and the one with the gauge. If you go to RockAuto, you will see the options for the sensor with gauge and without.

And yes, this is the sensor located at the back of the engine block, driver side.

 

Old-school gauges use a coil that produces a magnetic field which tugs the needle over. The sender is just a variable resistor on the ground leg of the coil, so basically it modifies the strength of the current passing through the coil, producing variable strength magnetic field. So an easy test is to disconnect the sender wire (circuit open with no path to ground) and see if the needle falls to the bottom of the gauge, then short to ground directly with a piece of jumper wire (circuit fully closed with no resistance) and see if the needle pegs to the top. If you get the full swing, then the gauge is fine and there's a problem with the sender