lights out

88 XJ limited, 4.0. Noticed tonight that all of my taillights, side marker lights, front running lights (the ones below the headlights) are all out. The headlights and fog lights are the only ones working. The brake lights work fine when the pedal's depressed.

If it was just one, I'd say a bulb was out. All of them out makes me think it's something else. Was hoping one of youse might point me in a direction of where to start in tomorrow morning. Is there some relay or something that all of the lights run thru? If so, where is it/what's it look like?

Thanks gang.

I'd start with the headlight switch or the multifunction switch (turn signal).

I am fighting the same thing right now. Person who owned the Heep before me put 90/100W headlight bulbs in, so the headlight switch burned out. To start with, the headlights would blink on and off, and got progressively worse. I think the tail lights may have also stopped working.

We replaced the headlight switch, after I build a complete headlight relay assembly, and replaced the bulbs with 55/100W units. After the headlight switch replacement, the headlights work fine. However, I don't have side markers, tail lights, etc. with the headlight switch in the on position. If I put the headlight switch in the parking light position, the parking lights, side markers, etc. come on.

We tried three different headlight switches, so it is not a new defective headlight switch. If it possible we also burned out the multifunction switch? The headlight switch had significant burning on the B1 terminal.

David Bricker / SYR

Well...I thought I had fixed it. My first check was the fuse box, and yep: the 10a fuse for the parking lights was blown. Put another 10a in, pulled the headlight on to check, and promptly blew the new fuse.

I put a 15a fuse in, and it lasted a little longer...long enough for me to hear the "headlight left on" buzzer for a couple seconds while I got out to check the rear tailights, and then it blew as well.

I had a 30a fuse, and thought I might put that in, but then I thought it might hold and burn up something else that I'd have to track down.

So...talk to me about headlight switches. I had no idea they even burn out. What's the method of swapping them out? PITA factor? Cost? Is the switch under the hood, or behind the dash, buried somewhere?

Any way to check if the headlight switch is bad before I go thru the trouble?

wgregt said:

Any way to check if the headlight switch is bad before I go thru the trouble?

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I don't know if there is a good way to check all the circuits going thru the switch. I'd say replace it, not that expensive.

I found that poor trailer wiring was causing the gremlins on the MJ. Not necessarily incorrect, just sketchy, poor connections. When I removed the existing trailer wiring, everything lit up.

The running lights and instrument panel lights should be on the same fuse (like on almost every other vehicle I've ever had, foreign or domestic). So if your dash lights suddenly go out you can bet your running lights are out too.

Climb under and check for any bare wires or other wiring gremlins, shoddy connections, etc.

OK. I guess I'll look into ordering a new HL switch. I do know that for the past, oh...15 years that if you turned the HL knob @ night (when dimming the dash lights) there was a point that it worked like an on/off switch if you hit it just right. It would dim up & down for most of the range, but would go on/off if you jiggled it right. It wasn't a big deal...I just lived with it. Might have something to do with the switch going out finally.

Anyone done this swap before? I'm guessing I need to pull the dash panel and go from there. Any special tools, tips, etc?

Your connectors could be badly corroded at the fuse box.. where the fuses go in.. reason I think this is because of how the 15 amp fuse "last a little longer" over the 10 amp. So.. drop the fuse box and look behind it.

Replacing the headlight switch is a bit of a PITA. On my '95, you remove the steering column surround. This lets you remove the instrument cluster surround. Now you can remove the instrument cluster. Next, remove the lower trim panel beneath the dash. Now you can remove the headlight knob by pressing the retaining latch on the switch, accessed from below. then unscrew the nut holding the switch in the dash. Finally, unplug the switch by reaching through the empty instrument panel area.

The switches aren't terribly expensive. Auto Zone was $20. Napa wanted $48. The two switches looked virtually identical, maybe there were internal differences. Rock Auto was $17, I think.

Once you get the switch out, inspect the connectors for any burning. Mine was burned on the B1 terminal, which supplies power to the entire switch. Also check the connectors in the cable harness. You could take an ohmmeter and measure the connections in the various positions, but for $20, throw in a new switch. The hard part was getting it out of the dash.

David Bricker / SYR

The dimmer for the dash lights is on a rheostat on the front of the switch, and really doesn't have anything to do with the switch itself. They get pitted, which is why some spots act like an on/off switch - they lose connection at those spots.

David Bricker / SYR

no-one has mentioned this yet, but fuses blow for a reason. you have a short somewhere if they keep blowing don't keep putting bigger fuses in it until they stop blowing out, you're going to start an electrical fire :doh:

i have seen this prob 2 other times, both times it seems someone had remove the rear hatch cover and saw there is a pair if wires(female-male) one blue one black, well thinking male goes to female they were pluged together and therefore lied the problem in both circumstances!! just an idea guys! good luck

tj'sxj said:

i have seen this prob 2 other times, both times it seems someone had remove the rear hatch cover and saw there is a pair if wires(female-male) one blue one black, well thinking male goes to female they were pluged together and therefore lied the problem in both circumstances!! just an idea guys! good luck

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NO F'ING WAY!! I JUST DID THAT! Is THAT why this is going off?

I had the rear hatch off b/c of a speaker issue, saw they were disconnected, and thought "Hmm. Must have come loose." Hooked them back up, and...promptly started blowing fuses a few weeks later (though the lights may have been out the entire time...never noticed it.)

Sheer genius. And I was just about to spend the day @ the junkyard looking for an OEM switch. Now I'll just go out and unplug those two wires.

Thanks for giving me my sunday back!

PS wonder what those two wires are for anyhow?

GrimmJeeper said:

no-one has mentioned this yet, but fuses blow for a reason. you have a short somewhere if they keep blowing don't keep putting bigger fuses in it until they stop blowing out, you're going to start an electrical fire :doh:

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Way ahead of you Mike. Fuses are the weak link in the chain for a reason, right?

I think I got this figured all out though. See post above.

tj'sxj said:

i have seen this prob 2 other times, both times it seems someone had remove the rear hatch cover and saw there is a pair if wires(female-male) one blue one black, well thinking male goes to female they were pluged together and therefore lied the problem in both circumstances!! just an idea guys! good luck

Click to expand...

I did the same thing on my 88. I saw some plugs that matched up in the hatch when I was replacing the rear speakers. I plugged them together. I mostly drove it during the day and didn't notice it for weeks. It got me pulled over one night. I cost me $300 at the mechanic to figure it out.:dunce:

92tahoexj said:

I did the same thing on my 88. I saw some plugs that matched up in the hatch when I was replacing the rear speakers. I plugged them together. I mostly drove it during the day and didn't notice it for weeks. It got me pulled over one night. I cost me $300 at the mechanic to figure it out.:dunce:

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You too? Exact same jeep and story I have. Had rear speaker problems, saw the wires loose, plugged them in, only drive it occasionally during the day, didn't notice it for weeks until I saw the alarm no longer blinked the lights on & off.

(BTW...I wish someone made some better direct-replacement speakers for the rear other than 5.25" 2-ways without having to find room for some sort of big-ass box enclosure.)

This is nuts. Wonder what those two wires are for then?

I just replaced the front ones with some 6 1/2" Pyle component speakers off ebay. Costs about $40. Mounted the tweets on the a-pillar. It sounds way better. Keep the fader 1 or 2 clicks towards the front and I can't tell how crappy the 5 1/4" 2-way kenwoods sound.

A quick search on crutchfield shows that a lot of companies make 5.25" 3-way speakers now? Wow. Hmmm.....Anyone tried/heard any of them?