‘96 Cherokee Country Mysyery Wire

Have a 96 Cherokee Country, 4w Dr, Auto, 6cyl-4.0. Replaced engine but have one wire we can’t figure out. Single conductor with a plug and a mating connector with what looks like a small lug coming out of the firewall bundle with the same cables that go to the fuel injectors. Too short to go to anything I can see. Thought it was a ground but grounding makes the coolant temp gauge goes full hot. Unhooked the temp guage does nothing. Any ideas?

 

That looks like a coolant temperature sensor still attached to the plug and wire. It is in the right place for such. I don't see any threads so maybe it broke off in the head. This could be the reason your original motor ran dry of coolant. Makes me wonder how this happened. That would have taken a pretty hard hit with a wrench or some other hard object.

 

Maybe.... The coolant sensor up front on the water pump is connected and appears to be working...it checks ok and the electric fan comes on at temperature or when unplugged. Is there another temperature sensor somewhere back there that I'm not finding? Where should I look?

 

Very back driver side of the head. Between the last injector and the stud where the ground strap is attached.

 

Yes, it should be right there but it isn’t. Any other places they might have put it?

 

Is this the old motor or the new motor you are taking a picture of? Pictured is what should fit that plug.

 

This is the new motor. The old motor had it that spot but not the new one.

 

I am thinking that the bolt and stud can come out and the sensor will thread in its place. There is a flat spot next to it covored in black oil. There isn't a flush Allen key plug there covored in oil/grease is there? You can double-nut that stud to unthread it out.

 

The ground strap to the firewall needs to attach to that stud. It is a head bolt if I remember right and does not need to be removed .

The milled flat, circular spot in the casting on the head shown is where that sensor needs to go. Looks like it has either a newer head or an entire newer motor in it.

~Jeff

 

What year is the engine and what is it our of?

 

The original motor was replaced with a used motor from SW Engines. It was ordered for the '96 Cherokee but I d

on't know what year the motor actually is. Most everything else swapped easily. ​

That connector is what looks like was in the old motor in that flat spot Offgrid mentions. I'll get in and take a close look to see if there may be a removable plug in there. If there anyplace else the sensor COULD go easily?

 

Appears the engine is out of a later model XJ, hopefully it's not a 2000-2001.

Looks like some people have put a T fitting in the thermostat housing and extended the sensor to the front.

 

That option works pretty well, other option is to drill and tap that spot on the head and that is a pain.

~Jeff