Engine won't turn off with headlights on

[Cheapamanche]

I have a 1988 comanche 4.0 that occasionally stays running with the key off if my headlights are on. When I turn back the ignition the dash lights dim down and I have to turn off the headlights to kill it. Maybe it's always done this and I only notice it when I forget to turn them off first. Now obviously this is an electrical problem but I have no idea where to start. My fear is one day I won't be able to kill it even with switching the lights off. I have completed steps 1 through 5 and other random ones.

    Could this have something to do with the fuse box? I just have no idea where to start.

[jdog]

I would pull the fuse box out to inspect the back side, the other thing would be the bulk head, could be that the headlight harness got hot and melted and is now melted with a ignition wire. other thing you could try is if you can get it to do it again, start pulling fuses see if any kill the vehicle then you would have an idea of a circuit.

[Cheapamanche]

That's a great idea on pulling the fuses. I will do that. The back of the fuse box is pretty crummy. I had a master cylinder leak a while ago. Maybe I should unload a whole can of electric parts cleaner on the thing to try and clean it out a little before deeper surgery.

[jdog]

poor design on jeep on that one. I would clean it and the bulk head just to see if it helps.

[JustEmptyEveryPocket]

Honestly and unfortunately, since you had the MC leak you need to replace the fuse box. It is going to give you more issues down the road, some of them potentially very dangerous and all of them unexpected. This is a time to fix it once and fix it right.

[Cheapamanche]

Your probably right. It's in rough shape.

[Cheapamanche]

I got a chance to tinker with it for just a little today. When I turn the headlight knob, it controls the brightness of my running lights instead of my instrument lights. 🤔

[BeaterComanche86]

How melted is your headlight switch? 

I had similar issues, and mine was pretty toasted