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Aftermarket Oil Pressure and Water Temp Gauges


NAXJA Forum User
I want to install aftermarket electrical oil pressure and water temp gauges on my 98 XJ 4.0. For the pressure sensor should I remove the factory sensor and use that port for the new sensor and if so how do I disable the dummy light? What would be the best location for mounting the temp sensor? I know this is a very basic question however this is my first guage install so any information or ideas you have would be appreciated. The factory Autometer guage instructions only give the electrical specs with no mechanical info. Thanks in advance.
For the oil pressure sender-remove the factory sender and screw in the one for your new guage.
Now the water sender may be more complicated.On my 96 I used the same hole as the factory sensor-at the rear of the head,BUT on the wifes 98 there is no hole at that location.
You may have to put a "T" fitting in the thermostat housing and install the sender there.
Just let the wires to the old sensors hang free.
I haven't done that before, but you may add a t-junction at every sensor hole on the engine and add your new and old sensors there. I am not sure where the tell-tale light gets its signal from, or anything else, but with this way, you can have both old and new gauges together (or just the new and the telltale).

I might need to do the same, since my temp gauge does not move out of the blue area at the left, even at normal op. temperature. I am changing the temp sensor as a first step, then I'll see.

Has anyone actually replaced the in-the-dash gauge with an aftermarket one? Can it be done?

I put a small electric (2") water temp guage in the area to the right of the instrument cluster.In my 96 this was an empty panel.The depth is not much,and everything fits tight.
Don't use a T fitting for the temp guage. It has to have water flowing past it or it will not give you an accurite reading.

Wich sender does the computer read the engine temp from? You will not want to remove it or the engine computer will not function correctly.

You would be better off just buying a factory guage dash and putting it in. You will see them for sale here or on jeepsunlimited from time to time.
I have the sensor for the PMC and a sensor for an aux fan switch mounted in a "T" fitting and they are within 1/4" of touching each other. Both are in the coolant flow and both work correctly.