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2G Headlight circuit meltdown

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TWOpointFORliter

10+ Year Contributor
644
120
Jul 31, 2009
Crown Point, Indiana
So the other night I had a small electrical fire in my car. After doing a small highway pull I had smoke coming from my steering column. I ripped the plastics apart on the side of the road to find the small wires that go from the headlight/turn signal switch to the actual hand lever had melted and were sparking/on fire. I separated the wires the best I could and made the decision to drive the car home since I was only a couple miles from home.

When I got home and shut the car off my headlights stayed on but it was late so I killed the battery and went to bed. The next day I switched out the headlight switch in the column but my headlights were still stuck on. They will shit off if I pull the headlight fuse and turn back on when reinstalled. I went through the motions of the new headlight lever also:
-turned the parking lights on and they came on along with the tails.
-turned the headlights on and the seemed to get brighter
-turned the brights on and they came on like normal
-activated the turn signals and the switch started to smoke again.



Killed the battery and started going through wiring again and that’s when I found the wires behind the fuse box had melted together on the headlight relay. The meltdown behind the fuse box appears to be caused by one small red wire from the headlight relay that appears to have gotten ver hot and melted everything. This was a section of my new relocation harness so I pulled that interior section completely out and inspected it. The only damage appears to be behind the fuse box and all the factory wiring shows no signs of damage either.

A couple of questions:
- why didn’t my headlight fuse pop and prevent this?
- Is it more likely the problem started at the switch or behind the fuse box?
- Could the fuse box melt down been caused from my drive home with a hot circuit? Like I didn’t get the wires that were sparking in the column separated good enough?
- is there anything else I should be checking as a possible cause to this?
- I have led tail lights that cause my turn signals to flash faster than normal because I haven’t added a resistor. These have been like this for almost 10 years without issue. Didn’t know if it was possible that the circuit/relay/switch overheated from sitting waiting for traffic to clear with the turn signal on.
- I had the column plastics apart a couple weeks ago and I guess it’s possible I pinched the wires that melted in the column when I put it back together?

Any help/ ideas is greatly appreciated. I am not very good with electrical systems but I’m not completely ignorant to them either.
 

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This may not be much help, but back when I use to run HIDs in my headlights. I had a ballast go bad and fried most of my wiring to the passenger side headlight. It also never blew the fuse.
 
No idea why the fuse didn’t blew, but if you might have the wire getting contact with another one, you have to trace the wires and see if where is the fault, also you have to change the wire completely which is all ready burned and will not be able to carry the current the head light needs.
 
No idea why the fuse didn’t blew, but if you might have the wire getting contact with another one, you have to trace the wires and see if where is the fault, also you have to change the wire completely which is all ready burned and will not be able to carry the current the head light needs.

The wires between the fuse and the headlights is fine and part of a brand new harness. The wire that burned up and caused the melt down is going between the relay in the engine fuse box and the switch in the column. I’ve got the dash out and I am tracing the wires on the factory interior harness between the headlight switch and the interior fuse box but they all appear to be fine. Can’t find anything melted or bare
 
So you are saying you melted the headlight TRIGGER WIRE?.

Yes? Like I mentioned I’m not very savvy when it comes to electrical or wiring diagrams. This was the smaller gauge red wire that appears to go between the headlight relay in the fuse box and the switch on the column.
 
Ha ok, I got it.
There is no way that wire to produce such current to be able to melt the way it did, Another wire might get in touch with it and did the disaster.

The way it didn’t blue the fuse is, because that wire is not fused, it still in the headlight circuit but because is only a trigger/signal wire, is very low voltage.
The only fused wire is the one carrying the high voltage which comes from the battery to the relay to feed the headlights.
 
Ha ok, I got it.
There is no way that wire to produce such current to be able to melt the way it did, Another wire might get in touch with it and did the disaster.

The way it didn’t blue the fuse is, because that wire is not fused, it still in the headlight circuit but because is only a trigger/signal wire, is very low voltage.
The only fused wire is the one carrying the high voltage which comes from the battery to the relay to feed the headlights.

So it seems more likely that the wires melted behind the fuse box and sent power through that trigger wire to smoke the switch in the column as opposed the the switch melting and sending power back to the fuse box? I just dont want to get my harness fixed and then have all happen again once it’s reinstalled. I have good buddy who is a excellent mechanic that is gonna come over and help me go through everything. I was just hoping for some insight on anything that could have caused this besides finding a bare wire somewhere.
 
Yes, that is most likely to happen.
Just fix all the wiring and remove the headlight relay, once you hook up the battery and see all is good, place the relay and pay attention in the wires, but to be honest, I would replace the relay or even swap it for a minute, just to try it at the beginning to make sure is the relay is messing anything.
 
Yes, replace the relay with a new one. With the other harness wires looking good, the only way the trigger circuit could have experienced that much current, is if the two circuits got crossed up inside the headlamp relay.
 
Well hopefully you fixed this issue. At the very least that section of wiring could be pulled from any 2g shell in the junkyard. Probably from a dodge or Chrysler too.

That's sucks. I would have shit myself haha. Glad it wasnt worse.
 
I just wanted to close this thread out since I believe I’ve found the cause of this since everything is working fine after getting my repaired harness back in the car. Long story short I learned something new about my car today that I’m surprised I’ve never come across in all the years I’ve browsed these forums. Found out there are 2 different style headlight/turn signal switches and 2 different covers for the steering column and if you mix them up it can eventually cut through the wires and short out. I don’t know if this is common knowledge and I’m just dumb but I figured I’d post some pictures in hopes it may one day help someone else.
 

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