Since I have the truck I never got a clue of what this sensor is exactly controlling and why it has this peeled green wire that attached to another brown/yellow on some harness near the firewall. The temperature gauge never gave me a noticeable problem until the last week. My temperature gauge is suddenly fluctuating the temperature readings so bad and I ask for some help in autozone and the guy told me that there are actually 2 temperature sensors. I googled it and I could not find a switch with a connector in this particular position. Any ideas to get the correct switch and connector to make it work like it should?

Since I bought the truck the cooling fan is at 12v all the time, so I don't know where to start to check components in order to get my fan running and turning off only when it's needed. What could be wrong with this problem?

Thanks for your help!

 

Pre 97 xjs have two temp sensors. One is on the t stat housing for the computer. The other is tapped into the head on the right towards the back and is for the instrument cluster.
These were combined into one on the t stat housing for 97 and up.

It appears that yours has an aftermarket housing or tapped factory housing to take the place of the sensor on the head.

 

Note from DJ
You probably have a 97 plus head in a 96 back Jeep
Have a look at this old post for further information

Relocating two temp sensor/help figuring out threads:
http://www.naxja.org/forum/showthread.php?t=1045608
Op by zluster
Ok so I am using a 01 XJ engine in a 96 XJ, got it running last night but I have this one last problem to solve.

 

Yup. The thread you posted me here explains a lot of things that I am understanding now. As you can see there is not a tapped hole in the head where the gauge sensor is. Is more than evident that I have the head from another engine, probably XJ, probably YJ, I don't know

Rust and oxidation in the head area are very noticeable in the second picture.

Any ideas to get a connector for the actual gauge temp sensor in order to get it better attached than the raw wire to it?

How can I deal with the cooling fan that is running all the time?

Thanks for your help, guys!

 

On the early XJ's the temp switch for the radiator fan is on the radiator . I think it is on the drivers side of the radiator .

 

All right. Updates for this thing!
I replaced both sensors cooling temp and temp sending unit (I learned fixing this that is NOT actually a switch)
Duralast Coolant temp sensor and Duralast temp sending unit TU108.

For the electrical 12v constant in the electric fan, it was because we found that the relay was connected directly to ground. Just routed wires as they should be.
I tested the correct behavior of the harness sending the signal to the electric fan disconnecting the coolant temp sensor and the electric fan started to run. After I reconnected the coolant sensor it just stops spinning. Works like a charm
Now the thing I noticed about the temp sender is the following (picture attached)
The engine was completely cold when I changed both sensors. Temp sender could be so thigh or so loose? As you can see "reads" temperature while it is not reason to do that
What can I do?

 

Yeah my needle sits in the same spot when the ignition is off. It will also stay in the middle when you shut it off and it's at 210.

 

If your engine block to firewall ground still looks like this, you should bolt it down and make sure the other end is attached. Clean connections to shiny metal.

 

On my 95 the gauges read wherever they were at shut-off as well.