Zj lighting problems

7716 Views 23 Replies 6 Participants Last post by m.o.sundelin, 1 mo ago

bshank71

Discussion Starter · Mar 27, 2016

I've heard this is a common problem in zj' sand I've had it for a little while now and can't figure it out. I have a 98 zj and the dash lights and running lights (tail lights, marker lamps, and fog lamps) are not working. It keeps blowing the fuse for them, however, my head lights, turn signals, and brake lights work. I've taken the dash completely apart several times, checked all fuses (cab and engine bay) and traced wires until I was cross eyed, and I still can't seem to figure it out. Anyone had this problem and know how to fix it?

1 - 20 of 24 Posts

Gluckmysock

· #2 · Mar 27, 2016

Do you have a tow hitch? If so, check the trailer connector plug. It also is spliced into the factory harness behind the Left Rear quarter panel. Make sure the bulb sockets in your rear tail lights are not corroded. Does the fuse blow whether the fog light switch is on or not?

BTW, Welcome to the forums.

DaingMaing

· #3 · Mar 27, 2016 (Edited)

bshank71 said:
I've heard this is a common problem in zj' sand I've had it for a little while now and can't figure it out. I have a 98 zj and the dash lights and running lights (tail lights, marker lamps, and fog lamps) are not working. It keeps blowing the fuse for them, however, my head lights, turn signals, and brake lights work. I've taken the dash completely apart several times, checked all fuses (cab and engine bay) and traced wires until I was cross eyed, and I still can't seem to figure it out. Anyone had this problem and know how to fix it?

It sounds like you could be having a headlamp switch problem. All of those circuits converge in that switch module. Do you have a spare to see if it's the switch? Should be cheap at a junk yard. I'd also check the parking lamp relay and fog lamp relay.

It sounds like it also could a grounding problem, perhaps a short somewhere in a harness, if not then a splice problem, and then maybe a connector at the junction block problem.

I just had an issue with my vanity lights, map lights, and dome light over the rear seat wouldn't come on when the courtesy relay switched on. I had lights in the wheel wells and doors but not up above. I did not have any issues with the fuses though. I got out the FSM and looked at the wiring diagrams before doing anything. I concluded that either I had a bad ground somewhere, a splice shorting out or grounding out, or a bad junction block.

I spent some time recently doing the fog lamp mod for my ZJ, and while I was in there; I spread dielectric grease all over those dirty bastards. I plugged everything back in, and it worked. This is not the first time I had an issue with a junction block connector not making solid connections. I had a tail light issue for a bit about 6 years ago.

http://www.cherokeetalk.com/forum/f9/zj-fog-lamp-mod-62890/#post926802

Go ahead check the headlamp switch and grease those bastards up and if those two things don't work; come back and post up. I can give you FSM diagram/wiring schematics if you need them. Also, try to see if there is any other circuit or things in the rig turning on when they're not supposed to.

We can get 'er done.

Welcome to the boards!

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bshank71

Discussion Starter · #4 · Mar 27, 2016

Thanks for the warm welcome. I've checked all the wires I could including the trailer harness and couldn't find any breaks anywhere. When the problem started I tried swapping the switch and it didn't seem to help. The fuse blows almost as soon as I turn the lights on whether or not the fog lamps are on or not. When I mess around with everything (taking dash out) it will stay and work normal for a couple minutes and seem as though it's fixed but as soon as I go to drive off it blows the fuse. I've also replaced the park lamp relay and it didn't seem to help either.

Gluckmysock

· #5 · Mar 27, 2016

Have you checked the light wiring at the shifter. May be a long shot, but you may have a bare wire there and it only shorts out when you move the shifter. :thumbsup:

DaingMaing

· #6 · Mar 27, 2016 (Edited)

So we're gonna need to know which exact fuse keeps blowing. I'll rustle up the FSM diagrams and we'll go over it; unless you've already got the diagrams?

At this point after hearing about your issue, even when the dash is apart; I am leaning towards a punctured wiring harness somewhere. A short is drawing too much juice through that circuit and it pops the fuse. That is about the simplest solution I can think of right now. You said that you've had the harness pulled apart before?

bshank71

Discussion Starter · #7 · Mar 28, 2016 (Edited)

I haven't pulled the harness but I've traced it as far as possible through the dash and under the center console and haven't found any evidence of a broken, frayed, or disconnected wire. The only thing I have left is to pull the cab fuse box and check behind it. As far as the fuse it's number 17 rad illum.

I also have another issue that isn't as bad but is just as confusing. My interior (dome) lights stay on when there is a fuse in place (#16) but the dimmer is all the way down and all doors are closed.

I have the book for the truck so it has all the diagrams in it but as far as wiring diagrams go I'm completely useless lol.

Gluckmysock

· #8 · Mar 28, 2016

This may help add some "value" to your abilities!

bshank71

Discussion Starter · #9 · Mar 28, 2016

Lol hopefully it'll help out!

bshank71

Discussion Starter · #10 · Mar 28, 2016

Does anyone have any theories on what else could cause this problem and where to look that I haven't mentioned?

DaingMaing

· #11 · Mar 28, 2016 (Edited)

bshank71 said:
... As far as the fuse it's number 17 rad illum.

I also have another issue that isn't as bad but is just as confusing. My interior (dome) lights stay on when there is a fuse in place (#16) but the dimmer is all the way down and all doors are closed.

Okay that is a big red flag.

The dimmer switch is in the headlamp switch as well. That group of wiring to the switch would be where I started looking for the issue.

Will you explain this a bit better? you're saying that the interior dome, map, and courtesy lights are always on with a fuse in the #16 spot and never turn off? When the gauge cluster lights do work, does the dimmer slider control the brightness when the headlamps are on?

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bshank71

Discussion Starter · #12 · Mar 28, 2016

DaingMaing said:
Okay that is a big red flag. The dimmer switch is in the headlamp switch as well. That group of wiring to the switch would be where I started looking for the issue. Will you explain this a bit better? you're saying that the interior dome, map, and courtesy lights are always on with a fuse in the #16 spot and never turn off? When the gauge cluster lights do work, does the dimmer slider control the brightness when the headlamps are on?

Yes the dome lights stay on when there is a fuse int the #16 spot. The gauge cluster is controlled by #17 and continues to blow fuses. The dimmer does control brightness when the lights work

DaingMaing

· #13 · Mar 28, 2016 (Edited)

Either you have a short in the harness that connects to the headlamp switch, the headlamp switch is bad(most likely), bad parking lamp relay and/or bad courtesy lamp relay, or you have a bad BCM.

I just don't see anywhere else you may have an issue. If something was just not working or getting juice that would be one thing, but your shorting out extra juice from the 17 fuse circuit. Fuse 16 giving you constant juice to courtesy lamps without courtesy relay being active is where your juice is going to from fuse 17. All of your symptoms come from this switch and I am hard pressed to think of anywhere else you may have an issue. Bad Switch, Bad Wiring in the connector/harness behind the switch or bad body control module.

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bshank71

Discussion Starter · #14 · Mar 28, 2016

But that's the part that drives me up the wall. I can't find anywhere the wires are messed up, the bcm is good supposedly, and I've already swapped the switch.

bshank71

Discussion Starter · #15 · Mar 28, 2016

I was doing some looking around earlier and I remembered my park/neutral safety switch is out and it's keepin my reverse lights from coming on. Do you think that might have anything to do with it?

DaingMaing

· #16 · Mar 28, 2016

It might cause a slight problem with the rear lighting, maybe if there is a short back there, but that would be quite complicated for it to cause all of those systems to fail at the same time. Things like this tend to be the simple solutions in my experience; which may not be all that much to some.

I still think everything converges on that area of the dash...

maybe pull apart your switch and have a look at the contacts in side? it may show you something, or maybe not. I too would bat a loss if this was something other than that switch or area of the harness.

bshank71

Discussion Starter · #17 · Mar 28, 2016

I'll give it a look see hopefully tomorrow or within the next couple of days and see what's what. Hopefully it is a simple fix but I have seen some pretty weird stuff cause a hell of a lot of problems.

CT99XJ

· #18 · Mar 28, 2016

Replace the actual switch module. A contact goes bad in there and you lose all the night lights

bshank71

Discussion Starter · #19 · Mar 29, 2016 (Edited)

So I finally got some time to tinker. Took a jumper wire and went through the connections in the plug and got my fog lights to come on, a couple dash lights from what I could see (it pretty bright today), and the marker lights to come on and the fuse didn't blow. Upon some further inspection I came across this #16 far right and #9 far left are burnt as hell. I wonder if that could be my culprit?

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CT99XJ

· #20 · Mar 29, 2016

Might be. Try resoldering the joints on the board.

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