Help! Jeep is smoking, electrical issue.

[CdnJeeper]

I need some help asap. My headlights have been flickering on and off and dash lights would sometimes not work. I was told to replace my headlight switch as it was common on cherokees. I was also told very old/bad switches could even start a fire if they short out. I didn't want this to happen so i bought a new switch asap. Now, I'm not on the road 20 minutes with my new switch installed and smoke starts coming from under my dash.

What the hell went wrong? Am I missing something? I have to rip it apart tomorrow in daylight but I'm pretty upset right now. Preventative maintenance just turned into fire fighting. Any help would be great. Thanks.

[NW99XJ]

the first step would be to get as much access to the area of concern... I see by your details, you have a 1999 XJ... same as me.
You'll want to remove the knee panel that is under the steering wheel... not a big issue, you may have done this already to swap out the switch.
You'll want to track down where the smoke came from... whether it was from the switch itself, the plug, or maybe a wire.
If it is the switch, we'll need to figure out where and why a short happened.
This issue was most likely created by some sort of short in the system..... but it's not the only possible cause.
The headlight circuit in a Cherokee is notoriously weak. Measuring the voltage at a headlight plug usually will give you about 10 volts, sometimes less.... awfully low when taking into consideration the 14+ volts that the alternator is putting out while the engine is running. But why? Typically there are poor grounds, too much wire in the system (ie; a bad circuit design) or corrosion issues... all create a resistance to the electron flow, or the path in which the energy likes to flow.
Often times a loose or corroded ground point will sit there and short to itself... .think of a spark jumping across a gap pf a spark plug... this isn't a short per-say, just the electron flow having to jump a gap to continue its flow.
Your issue COULD be a short, but it could also be bad wiring, connections, etc.
A corroded wire will present alot of resistance to the path of electricity. So much so it may not pass at all. Your flickering issue could be corrosion, maybe in the headlight plugs themselves.... the plug becomes loose, and the headlight will flicker. The same could happen to the plug at the harness for the switch. This could have been overheated due to a bad connection in the system, and become loose, affecting ALL of your lights.
The best bet is to remove the switch, and inspect it, the plug (bith sides) and of course as much of the harness itself as possible.
I did a full tear down and rebuild of my own headlight switch in my 99 XJ....
You can see the process here:
http://www.xjtalk.com/showthread.php?t=11357
Hopefully seeing the pics in that will give you a better picture of whats going on as you pull and rotate that switch in your dash.

Identifying where the issue is in your case will be step 1.
Repairing said issue will come next.
It's really quite hard to trouble shoot electrical problems thru the web, or even over the phone. So the best I can do is start going thru a process of elimination (the best way to diagnose and repair intermittent electrical issues) to determine whats going on.
Once we find the problem, the repair may be self evident, or come as common sense.
If not, well.... thats what WE'RE here for.
Pics always help. So as you take things apart, be sure to snap a couple pics here and there. In this case, I can stress the importance for GOOD lighting... doing this by the parking lot light of your local wally world prob isnt a good idea.
If you have or have access to a decent digital multi meter, it may help. As will a test light.
If you find no visible issues with the switch, plug or harness, it would be time to move on - although considering you saw smoke from under the dash, I would say you're bound to find something.
However, if you don't (I'd be surprised) ...then we'll want to take a look at the PDC (power distribution center) under the hood, and of course the fuse block inside the Jeep.
You'll want to look for fuses that are discolored, or corroded, this may involve removing each and every fuse individually, inspecting it closely, and inspecting its socket before you put it back.
I would ask that you also remove each headlight, and look at the back of each bulb, and pay close attention to the plug, and its wiring. Looking for signs of small shorts (blackening around contacts/contact points) and inspecting the harness for discoloration, brittle sections of wire, or areas where the shielding may have been pinched, broken, worn, or otherwise compromised. (this would apply to the inspection process of any/all wiring circuits)
Repair/splice/patch any areas of concern with new, or good condition used parts from a junk yard.

You may want to consider looking at all four corners of lights in the Jeep. Removing each lens/bulb one by one, and inspecting each harness, plug, wire and socket, to determine if you have something that looks out of normal. Some oxidation is normal, but if something is brittle, broken, exposed, or looks like its fuzzy or melted...well then you have your self an area in the system that needs to be repaired.
It's kind of like surgery!... you're on the hunt for cancer, and if you find some, you cut it out... only in this case, we're going to put something back in it's place.
So go put those scrubs on from the Halloween party a few years ago, break out some tools, and go get dirty.... post up some pics, and let us know what you have found... hopefully it's something obvious..... if not, well, report your findings and procedures, and we'll go from there.
Good luck!

[CdnJeeper]

wow thanks for all of the above help! I will definitely follow those steps when I look into it. To add, as it may help to figure out the issue, when I purchased the vehicle in march 13 I installed silverstar headlights from my old cherokee. Upon removing the harnesses the wiring snapped so I replaced both driver and passenger side harness with new ones from a local parts store. After doing repair I noticed a new issue but didn't do anything about it as it didn't bother me.

Sometimes when I start the jeep the high beam indicator is illuminated even if the lights or high beams are not on. When this happens, the jeeps DRL headlights will flicker but the lights work fine if I pull out the switch knob and turn the lights on full.

However, sometimes I start the jeep and the high beam indicator is NOT on and the DRL lights do not work at all... again, if i pull out the switch knob the lights work fine on full. I live in Canada and this is an American Jeep, the owner prior to me installed an aftermarket DRL module a decade ago (very poor wiring job) which I'm sure is causing an issue.

Also, from time to time I heard a squeaking/beeping/clicking noise coming from my old switch. It's a difficult sound to explain and I never thought much about it until now.

[CdnJeeper]

update, I found a broken wire leading to my fog lights, it had shorted and melted... cause of the smoke! Completely unrelated to the install of the switch.. just very very ironic timing that it broke.

Now, ever since I installed that new switch (i even tested it immediately after install) I still have no dash lights. I'm assuming the new switch is defective as the instrument fuse is good. I will put my old switch in again tomorrow and if it works the new one could be DOA. I will update tomorrow. Thanks for the help again!

[slvmart]

Just as a FYI ! I had a '94 Dodge Dakota that was also marginal with respect to headlight wiring. I forget, off hand, who sells the kit but there are headlight rewiring kits available that bypass much of the standard wiring with relays. It may be Painless. So all that the headlight switch does is provide the lower draw signal to power the relays. Here is a link to one site that gives you info about doing this: Wiring Headlight Relays (http://www.rowand.net/Shop/Tech/WiringHeadlightRelays.htm)
Here is the Painless link : http://www.painlesswiring.com/mobile/webcatalog/searchrefined.php?SearchAll=Trucks&refinesearch=Relay+Kits

[XJ Wheeler]

Got the Putco harness on mine... great upgrade and will help take draw off that headlight switch.

[NW99XJ]

update, I found a broken wire leading to my fog lights, it had shorted and melted... cause of the smoke! Completely unrelated to the install of the switch.. just very very ironic timing that it broke.

Now, ever since I installed that new switch (i even tested it immediately after install) I still have no dash lights. I'm assuming the new switch is defective as the instrument fuse is good. I will put my old switch in again tomorrow and if it works the new one could be DOA. I will update tomorrow. Thanks for the help again!

Ok, good info!... glad we're starting to narrow it down some. At least we know now what caused the smoke. I would have to say that the DRL Module is the culprit in all this. If your confident, I would remove that from the system, and patch any necessary connections... I bet all your problems go away.
As for the dash lights not working, but the fuse still being good, I would lay odds its the switch... if for some reason, after swapping in the old switch, and they still don't work... there may be an issue with the instrument cluster itself... easy to determine... if you have a friend with another late model Cherokee, it would be an easy swap, just to see if it works.
Glad to help out.... I will be looking forward to hearing what happens with the switch swap.

[CdnJeeper]

Update. All is fine now. The new switch was defective and has since been replaced with another new one. All of my lights work and no more fires. :)

A big thank you again to everyone for the help!

[NW99XJ]

OUTSTANDING!
I love a happy ending...
:D

[4.3LXJ]

Glad to hear it

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