stackz

ok, bone stock 1996 2.5 2wd 5speed cherokee.

the temperature idiot keeps coming on. hell, it even comes on before the truck is even warmed up.

I'm monitoring the temperature myself via another temperature gauge and its NOT overheating.

I replaced the temperature sending unit and it still comes on.

after looking through the 97 FSM I found elsewhere online, the wiring diagram shows the circuit goes from the sending unit, to the ecu, and then from the ecu to this CCD bus thing, then to the instrument cluster.

it appears based on the wiring diagrams that the 2.5 only has a single temperature sensor which is used for the ecu and for the gauge/idiot light.

where is the CCD bus? could this be bad? I'm also thinking of just swapping over to a regular gauge cluster with analog needles to get rid of the idiot lights and then see what the gauge itself is doing to help figure out the problem...

I mean hell, the gauge cluster is $20 at the u-pull and I can toss the oil pressure and temp sensor in my pocket lol.

I checked online and it looks like the 4.0 and 2.5 use the same oil pressure and temperature sensors so it should be that easy to do.

djb383

Thought I read that '97/later has 1 temp sending unit but '96/earlier had 2 sending units......one at the back of the head controls gauge/light.

stackz

I dunno but for the life of me I cant find a part number for a temperature sending unit for a 96 2.5 cherokee on autozone's site, advance auto's site, or oreillys site.

I would love to know for sure though lol. anyone know where its located on the earlier 2.5 engines so I can see if there's one in that spot? I'm downloading the 95 FSM now but figured I'd get a jump on it if possible since I'm on a super slow connection.

stackz

hmmm, after looking at the 95 fsm and the switch location and the wiring diagram which shows the actual connector, I think it does have a switch...

guess I'll just have to get one for a 95 and use that since I cant find a part number for a 96 online anywhere...

Karvin

If you have a secondary temp gauge... just pull the bulb out of your idiot light.

Just say'n.

stackz

I dont like ghetto'ing things up.

figured it out anyway.

original cluster itself was bad, well at least the temp idiot light was. went to the junkyard and pulled a gauge cluster with gauges out of another truck along with the oil pressure sensor and temperature sending unit. put it all in and the cluster is reading spot on perfect.

and I now have a tach and other gauges to boot! woot!

Karvin

Glad you got your situation resolved.

I don't see how removing a bulb, especially if you have another fully functional temp gauge, is "Gettoing". Unless of course you need/want the idiot light to tell you to look at your other temp gauge. Your dash likely has various lights to things like Full-Time 4WD that your vehicle wasn't setup for in the first place... at the factory they just don't put a bulb in. Jeep isn't the only company to do that, you will find it across the full spectrum of vehicle manufacturers.

stackz

no, its just that the gauge is an autometer one that I have the sensor plumbed into a piece of copper pipe and I usually tie it inline on my vehicles at the water pump outlet to the heater core and zip tie it in place. I just use it for diagnosis purposes and its just hanging around where-ever I set it when I use it....so yeah, it would have been redneck engineering lol.

I will say that the previous owner is a tool because when I swapped out the clusters, he removed the check engine bulb on me which is why I didnt know it was tossing an o2 code when I bought it...grrr.