Burning smell when headlights are turned on

I have a 92 with a bosch h4 conversion kit with 55/65 watt bulbs. Today while driving to work i noticed a burning smell from under the dash on the driverside. Someone at work suggested the head light switch might be burning out do to the after market lights. I used the search button and did a little research and i only read about people having the headlight harness or switch burning out when running high wattage bulbs?

Any idea of fixing this problem before my jeep burns down?

check your headlight swith really good, its probably smoked. it carries the load for the headlights. when you upgrade you really should do a wire and reley upgrade as well.

lazarus said:

check your headlight swith really good, its probably smoked. it carries the load for the headlights. when you upgrade you really should do a wire and reley upgrade as well.

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How can i tell if its smoked? What to look for?

look at it really close. you will be able to see the plastic discolored and have a nasty charred smell. also inspect the wire to see any insulation burnt and exposing bare wire

Just do a harness upgrade to relays. SHouldn't need to fix the headlight switch if it still works, since it won't be carrying any load anymore.

When you turn on the switch, feel the metal rod behind the knob. It is likely hot enough to blister your finger tip.
It's likely the instrument light dimmer part of the switch is messing up and cooking the connector. Best to deal with it before things melt down too far.
55/65 watt bulbs are OEM on the export models. They don't often cause high amp problems, though the wiring is a bit anemic, the switch (other than the dimmer) holds up well.

canadianwheeler said:

How can i tell if its smoked? What to look for?

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By the odor, LOL! :greensmok
Don't you just love the odor of burning PVC at sunset!:greensmok

I replaced the switch, and the push on parts of the connector, retermined the wires on mine in my 85 and 87 XJs and they were both stock. Smoked em both with only stock set ups. From the looks of the wiring harness connectors these were not the first head light switches to get smoked!:greensmok

As I recall my old ford LTD, '71, and my old dodge, 78 smoked the head light switches too once they were about 10 to 15 years old.

I never did a harness relay upgrade for my headlights, but I have done it for other high loads like the A/C blower,.....so it makes sense to consider it for the headlights!:eyes:

What Lawsoncl is suggesting is that you clean up and repair as needed the wiring harness connector, then replace the headlight switch (if needed), then put in a high amperage relay under the hood near the headlamps and use the old head lamp wires (coming from the headlight switch) to activate the new relay, then run fresh wire from the battery to the load side of the relay, then back out to the headlights. Then the headlight switch turns on the relay (very smal amp load) then the relay turns on the high amp load head lights.

The other option is to pick up pre assembled aux harness from rallylights.com or painless plus a few other shops sell them now. Your headlights will be much brighter too. If it was me I would replace the headlight switch and add the aux harness.
I had to do the headlight switch in my 97TJ last summer when it started going south, I wanted to beat 'the meltdown' so the plug did not have to be replaced too.

RichP said:

The other option is to pick up pre assembled aux harness from rallylights.com or painless plus a few other shops sell them now. Your headlights will be much brighter too. If it was me I would replace the headlight switch and add the aux harness.
I had to do the headlight switch in my 97TJ last summer when it started going south, I wanted to beat 'the meltdown' so the plug did not have to be replaced too.

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Preventative maintenance! Where is the fun in that? You don't really want to miss out on the THRILL of nightime driving in the pouring rain, windows rolled up, when the headlights start turning on and off at will and the dash starts really smoking :greensmok:gonnablow:shiver: and all that time you get the thrill of wondering if you will make it to the driveway and the fireway extenguisher in time, LOL.

:laugh3:

Now ask me how I know just how much that is!

Ecomike said:

Preventative maintenance! Where is the fun in that? You don't really want to miss out on the THRILL of nightime driving in the pouring rain, windows rolled up, when the headlights start turning on and off at will and the dash starts really smoking :greensmok:gonnablow:shiver: and all that time you get the thrill of wondering if you will make it to the driveway and the fireway extenguisher in time, LOL.

:laugh3:

Now ask me how I know just how much that is!

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Once you reach 'old fart' status preventive maintenance overshadows panic repairs...:yelclap:

The guy walks into the Doctors office and says he often has the smell of burning rubber in his nose. The Doctor says this is a sure sign of a brain Tumor and they will have to make some tests.
Guy comes back a week later and the Doc says all the tests came back negative. And asks is there any particula time and place you smell this and he answers in the bedroom during sex.

Pull the headlight switch to the parking light position, feel the metal rod behind the knob. If it gets hot it isn't the headlights.

RichP said:

Once you reach 'old fart' status preventive maintenance overshadows panic repairs...:yelclap:

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My problem is I spend so much time puting out :flame:s for everyone else I never get around to my own PM Roundtoit list until it's a :flame:ing issue itself. At least it makes it to my PM list, so maybe there is hope for this "old fart" after all.:laugh3:

I must admit, the more I think about it, a relay and heavier, shorter wires under the hood for the head lights with the original headlight switch used as the headlight relay control sounds real attrative!

Ecomike said:

My problem is I spend so much time puting out :flame:s for everyone else I never get around to my own PM Roundtoit list until it's a :flame:ing issue itself. At least it makes it to my PM list, so maybe there is hope for this "old fart" after all.:laugh3:

I must admit, the more I think about it, a relay and heavier, shorter wires under the hood for the head lights with the original headlight switch used as the headlight relay control sounds real attrative!

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You can buy it complete for $80 or build it yourself, recommendation, use the Hella relays with the built in fuses, makes for a neater install, none of those inline fuses hanging around.

X2^ did it on a bunch of old Mustangs and had much brighter, more reliable headlights for much longer:yelclap:

headlights worked better and the switches never died again-- not that I drove them too much (was resto-moding them for sale mostly)

safety is also improved due to less load in the passenger compartment:yelclap:

--Shorty

RichP said:

You can buy it complete for $80 or build it yourself, recommendation, use the Hella relays with the built in fuses, makes for a neater install, none of those inline fuses hanging around.

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Sounds like a Hellofa relay (LOL), so where does one find these fused hella relays?

Ecomike said:

Sounds like a Hellofa relay (LOL), so where does one find these fused hella relays?

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Anybody who carries hella should have them, they are blue case with a bayonet [GM,jeep]fuse on the side.

I don't know if anyone, besides me, has mentioned here but NEVER mount an unsealed relay upside down, they get a bit of condensation and it collects, eventually shorting the contacts out.

DAMN IT! I replaced the switch today and it there is still a strong burning smell. Any ideas?

canadianwheeler said:

DAMN IT! I replaced the switch today and it there is still a strong burning smell. Any ideas?

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Did you check the connectors and wires on the wiring harness to se if they were burned, burning, corroded, making poor contact? Mine was buring the PVC insulation on the feed wire to the switch. I had to replace the connectors as well as the switch on mine.

Only other place I can think of is the fuse box (on mine its behind the head light switch and dash on the firewall, 85-89) but I think yours (92) is under the hood?

Good news is the old switch was probably about to die anyway.

I followed the wires from the head lights to the firewall and didn't see much. All looks good. I guess i need to pull my dash apart and look for anything looking melted.