On my 96 4.0, it does not have a water temp gauge and I was thinking of installing one with a temp probe and a T into the radiator hose. My friend/mechanic said to not do it that way. He suggested I find the wire/sensor that warns the dummy light in the dash and bypass it to the gauge installed into the dash. Is this easy to do? Does anyone know which wire I need to tap into to make this happen? Are there any issues with the computer if I do it this way? Also, I have a gauge cluster that has all the gauges in it. One day I wanted to see what would work if I took the old one out and replaced it with this one. I can't remember but I think the speedo worked and that is it. Would it be easier to install the new gauge cluster and new sending units or just find the wire for the water temp?

 

Dealers choice here, I suppose it depends on how clean or "right" you want something to be. You are spot on with changing the sensors for the other gauages to work on your Non dummy light cluster. Which would be my choice in the matter fwiw.

Otherwise if its purely a function over form deal then simply install and mount the secondary gauge and probe. I don't believe you can just tap into a dummy light sensor to then pull a reading for a secondary gauge? Seems either way your potentially changing that sensor??

 

I swapped a full gauge cluster into my 96 4.0. Super easy. Just swap the cluster. You can swap or mess with the odometer if you’re picky. Then change the oil sending unit, and temp sending unit, for the ones listed for a 96 with gauges. The wiring from the sending units to the gauge cluster does not change.

The replacement cluster I got had the gray gauge surround. My stock one was black, so I swapped that too.

To specifically answer your question, you have to change the sending units. The ones for a light are simply an on/off switch. The ones for a gauge are a variable resistor. Simply swapping to gauges won’t show more information from the light based sending units.

 

There are two temp sensors...one on the thermostat which reports to the PCM.....and one located on top of the back of the head near the firewall...that one reports to temp light or gauge. Whether you disconnect the light and wire it to an electrical gauge or run a whole new wire would be the remaining choices.