There should be a relay in the circuit. It could very well be located in the power panel under the hood. The trouble could be with the control side of the relay. Also make sure the fuses have power getting to them if you haven’t done that already.
When working on problems like this you should use at least a test light probe to verify power and also have a wiring diagram, which it sounds like you do have, to guide you in your testing. You can then prove what is working and what isn’t.
Thanks everyone. I do not have power at the bulbs, but do get power on/off at the fuse when I turn the light switch on. I will start working my way back to see where the disconnect is. I hope a rodent has not chewed a wire somewhere
Check the power side of the bulb sockets with the meter’s ground direct to ground rather than into the other socket terminal. If they show power, check the ground side of the bulb sockets for continuity.
I tend to agree with a relay problem. Here is a diagram of your circuit. I not familiar with a “headlamp delay module” but it seems your Jeep has 3 of them. Good luck with your troubleshooting.
UPDATE: I found out that the headlamp delay module controls your headlights by way of the ignition switch. If you turn the headlights off before you turn off the ignition…the lights will go off normally. If you turn off the ignition before the headlights then the headlights will stay on for 45 seconds while you go inside your home. I knew about this feature but never used it in any of my Jeep Cherokees. I’m told if the delay module malfunctions…it can impact the turning on of the headlights.
I’m not sure. I know my 1996 model did. Just call a large local auto parts store and tell them you have a 1990 model Jeep Cherokee then ask them for the part.
thanks. I got a jeep not too long ago and can t turn off my lights if I shut the ignition off first. thought I had a malfunction, but have never waited that long to see if the lights will eventually go off. I ve had 1975 ford pick ups for about the last 15 yrs or so, so a 1990 jeep is high tech for me.
From what I see there aren’t any relays. From +12 volts first there’s a 30 amp fuse, then a 24 Amp circuit breaker, then the headlight switch, then the headlight dimmer switch, then the headlight(s) itself. It’s sort of odd they’d want to pass so much current through those switches. I’d suspect either the headlight switch or the headlight dimmer switch has failed. But check the circuit breaker too, you may have a short. & make sure a ground wire for the lamp sockets hasn’t come loose.
I finally fixed it. The Jeep is not my daily driver so I was not under a time crunch to fix it. I was about to do a brute force work around and put in new switches / fuse and by pass the original wiring. One multi pin connector that was not coming apart easily finally came apart, only had 12 vdc to the parking lights and not to the headlights. That pointed me to the fuse box. I took the box out and looked under neath it, all looked OK. When I probed the wire for the headlights, it moved, it had corroded away from the fuse holder. It looked like it had been cut and it had a nice copper patina. What a PITA to find a broken wire like that. I could not get the fuse connector out, so I jumper ed around and put an in line fuse in. I have lights and the factory switches work! BTW there are several versions of wiring for this year Jeep and none of them matched what I had, but between the various schematics I found I was able to piece enough info together, this one does not have a relay, I am surprised they put that much current through the switches. Thanks for all the comments and suggestions.
NICE WORK!!!
And I mean that sincerely. I tip my hat to you, clearly a man biased toward actual analysis/diagnosis. It gives me great pleasure to hear that.
If you’re not a technician or engineer of some kind, you missed your calling.
Many people use the lead from the switch to power a relay, which then switches the headlights. In other words, Creating the circuit Chrysler should have in the first place.