Need info on CEL wire to dash Grand Cherokee

[dennis461]

1998 Grand CHerokee
6 cyl
automatic
Need info on Check Engine Light CEL wire to dash.
I thinks it's been cut by a previous owner.
New computer installed.

Light bulb is OK, passed NJ emissions.
but Test but failed because the CEL would not light up during the testing.

Does anyone know which pin on the computer , or what wire colr runs to the light?

searched for wiring diagram but no luck.

 

[Sidewinder CC]

Re: Need info on CEL wire to dash

1998 Grand CHerokee
6 cyl
automatic
Need info on Check Engine Light CEL wire to dash.
I thinks it's been cut by a previous owner.
New computer installed.

Light bulb is OK, passed NJ emissions.
but Test but failed because the CEL would not light up during the testing.

Does anyone know which pin on the computer , or what wire colr runs to the light?

searched for wiring diagram but no luck.

I have an XJ Cherokee, not a GC, but I think the instrument cluster and CEL light work about the same (you'll need a GC forum to get the straight skinny on this).

I'm trying to figure out what you are saying in your post. You say the light bulb is okay, but then you say the CEL would not light up during testing. How do you know the light bulb is okay? How were you trying to make the CEL light up during testing?

The Check Engine light is powered from the ignition switch, through the (XJ) junction block (fused) to the instrument cluster, to the bulb. I think all warning lights on the instrument clusted are powered from the same source. The bulb is provided a ground through the circuitry on a printed circuit board (PCB) in the instrument cluster to illuminate it. The PCB receives it's information to illuminate the CEL from the PCM through a pair of wires called the CCD Bus.

The CEL should illuminate momentarily when turning the ignition switch to the RUN position, before starting the engine. If the CEL does not illuminate at this point, then the bulb is burned out, the power wire (on the PCB) to the bulb is broken, or the ground circuit to the bulkb on the PCB is broken.

Please explain your situation/problem a little better and perhaps a GC owner can help you out.

 

[dennis461]

Re: Need info on CEL wire to dash

We swapped the lightbulb with one that works, so we know the bulb is not burned out.
It never lights up, not when running, not with key on engine not running, never.

In NJ, when the state inspectors connect the vehicle OBD-II to the inspection station computer, they simulate a CEL ON condition.
This makes sure a vehicle owner has not pulled the bulb out to pass inspection.
So, if it does not light up, the car flunks inspection.
Computer is a rebuilt one and the rest of the state inspection was OK, so the computer is regulating spark and fuel just fine.

So, I think a previous owner has cut the wire.
and since the vehicle is a recovering from being stolen and raped, there are many issues with the dashboard wiring.

I'll probably have to get a real manual...

 

[Sidewinder CC]

Re: Need info on CEL wire to dash

I don't think you'll find a cut "Wire" to fix your problem. I would recommend getting a replacement instrument cluster from the junkyard.

Yes, a Factory Service Manual is a must for all Jeep owners that want to do their own maintenance.