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Headlight switch smoke

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Old 04-17-2016
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Headlight switch smoke

Hi all, a week ago smoke was coming from my dash, long story short the problem was the headlight switch so I changed it out along with all the fuses... Well since replacing all the fuses and the switch I've gone through two switches this week. The wire connector is perfectly fine it's just the switch that starts burning up. Anyone know why?
 
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Old 04-17-2016
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If it's burning up, that means there's more current flowing through the switch than what the switch is designed to handle. Resistance of switch, heat generated, all that happy fun stuff equals smoke.

I could be wrong, but I remember hearing something about a certain generation having a similar problem. I don't remember all the details, but I thought I'd throw that in there because it might put you or someone else on the same thought pattern I have.

I would take your old headlight switches and take 'em apart. Look for what parts are melting, and what pins those correspond to, and subsequently what wires they turn into.

By knowing what color wire(s) are affected, that will cue you in to what circuit is affected. If you have one, a good multi meter may be of some good help here. I have a fairly advanced autoranging multimeter off amazon for less than 40 dollars. If you want me to, I'll post the link for it.

A couple things to consider.
Does it melt when the key is on?
Does it melt only when in a certain position (IE, headlights on)

Both of those things can seriously cue you in. If it only melts when the headlights are on, there's your sign. If I remember correctly, these headlight switches are designed to take the load through the switch, while later model switches (04+ I believe) do not.
 
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Old 04-18-2016
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It starts smoking the minute I turn the truck on. Would it be a circuit issue or a relay?
 
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Alright, switch starts melting with key on, switch assumed to be off.

Unless a relay is compromised in such a way to where it's causing a short to ground (which is possible, but unlikely) then it's likely not. You can look at them if you want, but it's unlikely.

Somewhere, somehow, power flowing after the switch is being pulled directly to ground, allowing an absolute crap ton of current to flow through the switch.

Without knowing exactly what circuit is being affected, we're pretty much throwing darts at a map while blindfolded. Unfortunately, nothing relevant is coming up on google.

Were any modifications made to the truck? Anything new wired up? Any bulbs or anything electrical replaced?

If not, there's really only one way to see what's going on. Take the melted switch apart and see which pins are affected, thus resulting in what color wires they are which will pinpoint us to exactly what circuit has the problem.
 
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Old 04-18-2016
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The trucks absolutely stock. The ground seems fine and you're right Google has nothing on this. I'll end up taking the switch apart tonight and seeing if I can find what circuit is overflowing
 
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A stock truck is a good truck in this case. The less modifications you have to bear in mind the better off you are.
 
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Old 04-18-2016
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Would all this be a simple relay replacement under the hood or would I need to change out the wiring harness completely heck maybe both? Anyone know???
 
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The wiring is likely fine. What the wires go to however is a more likely situation. You can replace relays if you want, but that'll likely end up with no more than further cost.

But like I keep saying, the only way to fix the problem is to know what circuit is affected. Only then can we properly diagnose the problem. For all we know it could be the multi-function switch stalk. Get anything from disassembling the switch?
 
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Old 04-18-2016
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The switch internally looked fine but every wire in the harness coming from the dash was smoldering... They were all black/a very dark brown. I turned the truck on and sure enough they started smoking. I'm assuming I'll need to change out the harness. I'll go double check what wires in specific had it worse than others but now I'm just worried that if and when I change out the harness if the problem would persist. I'm also trying to find a way to bypass the harness so I can use my lights without setting my dash on fire
 
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If the wiring is damaged then it will need to be replaced. You may want to consider bringing the truck to a mechanic at this point. Without actually fixing the problem then the wires will just continue to smolder.

If you don't want to take it to a mechanic, then you can of course run new wires and switches for the headlights, park lights, etc. Just make sure you wire them properly, otherwise you'll end up with the same situation you have right now.
 
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Old 04-18-2016
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So I double checked, it's the red wire that's striped yellow and blue that's striped yellow that are smoldering. My mechanics soonest appointment is Sunday
 
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