Oh ok and im assuming you have tried replacing the sending unit?

Heres the schematic, i dont know much about the ECM but it looks like that could cause an issue? anyone else ever have that?

The hard part is testing the voltage coming into the unit, i think its a real low voltage, but thats what it basis the temp off of like .01v to .25v or something (not exact) but if the ECM is bad it might be effecting the sensor.

The copys suck but its the schematic for your jeep if i can get it to look better ill up it.

 

Crazy4x4Chick, I did some time in "The Valley". I'm not too familiar with any junkyards near Visalia but, there is a good scrap yard in Hanford. Take 198 to 11th Ave.....south away from town. There is also a decent one in Lemoore. Take 198 to 18th south. Go past the golf course and take your first right. About a mile and it's on your left. There is another JY just past it, don't go to that one. Go to the first one.

 

Crazy4x4Chick, I was just doing some Electrical Genius brainstorming. This may not be a broken wire (open) at all. Could be a short causing the gauge to stay at 0. If that wire going from the sending unit to the gauge is shorted to metal anywhere along the way, it will cause this. I'm still thinking where it goes through the firewall. Those firewall pass through holes are so notorious for the rubber grommets desentigrating and leaving a sharp metal edge for the wires to get nicked on.

 

With a sender for a "dummy light" if you have a gauge, it will move when you crank and then drop to the lowest mark. The sending unit for the "dummy light" and gauge look the same, only difference is.. the correct one works with the gauge, the other one doesnt. When I swapped in my "new" full gauge set, at first I did not change the cooling sending unit to see if it would work. With it installed.. when I cranked the engine, until it turned over it bounced/moved, when the engine was actually running it wend to 100 or the lowest mark.
When I installed the correct sending unit, it worked as it should. At very first it did not work, then I realized that when I puled it off the metal connector was "stretched" out a bit and not making complete contact. I used a pair of pliers to "squeeze" it back(make it so it would connect/fit) on the sensor and not move. and it worked perfectly after that. Make sure it fits snug on to the sensor.

 

I had that same problem. I tracked all the wires, grounds, and switched gauges. It ended up being that the wire backed out of the connector, so when you pushed the connector on the sending unit, it wasn't contacting the wire to the gauge. We actually found this out by taking the wire out of the connector and connecting it directly and it worked. We then put the connector over the wire and we had to shove the wire all the way in so the metal would make contact. Hope this helps.

 

The one in hanford kinda sucks, Pick-a-part and pick-n-pull are both ok i know the one in fresno has jeep parts (unless they got rid of them in the last few months)

What a small world...

But I would replace with new parts to make sure you fix the problem!

 

A1racer- Great Idea! Thanks

Jsny- Thanks for all your info. We will check the voltage this weekend and see what it is sitting at. They still have the ones in Fresno, I just havent been able to make the trip up there to get some parts. But I will have to do it soon because I need some interior parts and all the Jeeps ive come across dont have tan interior, which is what i need. Thanks for the scans! How exacly would I replace an ECM? if that is the problem?

Buck- There is one wrecking yard here in Visalia which has 3 Jeeps, but they have been completly taken apart! But I just found out they are having a 1/2 off sale this weekend... sooo I will be checking too see if they have restocked their inventory with more Jeeps. If not, then I will be trying the ones in Handford and Lemoore. They are closer than Fresno!

Metmknice- How would I know for sure I am not getting the 'dummy light' instead of the actual guage one? I would put my stock one back on (the one that came with the vehicle) but my hubby broke it after we rebuilt the engine and was lowering it back into the engine compartment. I will look at the connection and be sure the metal connector is connecting.

Cmuman- I will check into that as well. Thank you!

Ughhh I just want the weekend to get here so that we have time to actually work on it!

Thank you ALL for your input!

 

To be honest I dont know, I am betting its just the box under the drivers side dash but I have not swapped one out before on a Jeep.

Anyone done this or have a writeup? my chilton guide doesnt say.


Hope everything works!

 

So we FINALLY fixed my problem! We ended up checking voltage, which read that the wire had good volts. So we decided to run our own wire and it still didnt work. So we thought that somehow the origional wire was arching/grounding out on the frame and was shorting out the sending unit. So I ran to the nearest Kragen, got a new temp sensor, used our own ran wire and sure enough it worked! =D

So if anyone out there is have problems, try this:

Look at the sending unit (the one on the head) look at what the color of the wire is.
Remove your gauge cluster and find the same wire color
Run your own wire on the outside of the cab (no need to run thru the fire wall, if this isnt your problem)
Turn on the vehicle and see if the gauge moves to running temp.
If it doesnt work... dont give up yet!
Run to the nearest parts store and purchase a new temp sending unit
Install new unit, using same wire that you ran, check the gauge then...
And hopefully, like mine, this will fix your problem! =D

I just wanted to say thank you sooo much for all of your guys' information and advise!