Can anyone tell me where the coolant temp sending unit is located on the 99 4.0? Everywhere I search tells me it is on the drivers side rear of the cylinder head, but I can't find it there. I have the one on the intake manifold, and the one on the thermostat housing, but I cannot find the one to remove and tap in a mechanical temp gauge, and eliminate the idiot light. Any help would be greatly appreciated!!!!

 

It's in the t-stat housing.The one on the head are for 96 and down.

 

Is the sensor in the T-stat housing only the sensor for the warning light then, or is it tied to the computer for the open/closed loop readings? Can I simply replace it with the temp probe on the new gauge, or do I have to run the "y" fitting and share the port with the existing sensor?
Thanks!

 

I think you would have to run it with the stock sensor because it controls the electric fan and will throw a code if unplugged.

 

Unless they changed it you should be allright.I haven't had mine hooked up for almost a year and my CEL has never come on.

 

I tried unhooking the sensor to make the electric fan run constant in my 99 and it through a code and the gauge didn't work.