Coolant Temp Sensor

I have an '89 Cherokee, 4.0L. I want to install an aftermarket temp guage and noticed that I cannot connect the OEM coolant temperature sensor and the aftermarket sensor from the same port. I have read that later model XJ's have their sensor at the thermostat housing. If this is so could I replace my '89 thermostat housing for a '97 housing without any problem? that way I could Connect my aftermarket sensor to the thermostat housing and leave the OEM sensor on the block where it is now. Could someone please tell me if they've ever done this before and if it works? Also does anyone know when they started putting the sensor on the thermostat housing? Thanks alot for any help.

There are two coolant temperature sensors on your engine (4.0 I6 engine). One gives information to the computer, the other gives information to the dash guage. The one for the guage is on the rear upper corner of the engine, just behind the fuel rail. You can put the sensor for your new guage there, without interfereing with the engine control functions.

Bob is correct, but if you want to retain your stock gauge as well as the aftermarket, you can also replace the thermostat housing, as your original post suggests. Just remember that they are reading from different places in the coolant flow stream, so they should not be expected to read the same.

Thanks for the info. The main reason that I do not want to mess with the OEM sensor is because I do not want to interfere with the electric fan operation. Which sensor is responsible for the fan operation?

The sensor for the Aux fan is on the output tank of the Radiator for 87-90's

The 92 and newer XJ thermostate housing is what you need to get. I did the same thing you are doing about 5 years ago.