which temp sender/sensor does what?

I have a 95 xj and I am trying to get my water temperature gauge to work. right now it gets up to 155* and stays there (even if the Transmission goes up 50* from climbing a hil the motor stays the same temp ( I already replaced the T-stat)...What does the sensor/sender on the T-stat housing do/control and what does the sensor/sener on the back of the motor driver side on the head do?....Thanks

The temperature sensor at the rear of the cylinder head runs your gage. The temperature sensor at the thermostat housing provides a signal for the ECU, and the ECU uses this information to help with fuel mix and to drive the electric fan.

that's what I have been informed of from the JF web forum but I dd a test,I got a new sender, (leaving the old one still in the block) and connected the wiring harness plug and wrapped a wire around the copper sender core and wired it to ground. I boiled a cup of water and turned the car to on and the gauge did not budge when the sensor was lowered into the water. I also turned the motor on and nothing moved.... what am I doing wrong or what else could be wrong to cause this?

Magus2727 said:

that's what I have been informed of from the JF web forum but I dd a test,I got a new sender, (leaving the old one still in the block) and connected the wiring harness plug and wrapped a wire around the copper sender core and wired it to ground. I boiled a cup of water and turned the car to on and the gauge did not budge when the sensor was lowered into the water. I also turned the motor on and nothing moved.... what am I doing wrong or what else could be wrong to cause this?

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If it's not the sensor, it's a wiring fault somewhere. Start with the contact at the sensor itself (the part that slips over the screw thread) and work your way back. Good luck!

Does any one know what the Ohm reading should be for the Temp gauge at operating temp? Or if there is a graph that shows temp will display vs resistance of the sender?

This I wiggled the conection at the sender and it did nothing (no jumping or fluctiation at the gauge when playing with the conector), I have not done any thing or fidled with any thing in the lince between the engine bay and the insturament cluster.

If is there a way to test the gauge to see if it works?

Thanks for the help