Headlight switch wiring replacement
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8th Gear
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Headlight switch wiring replacement
About a month ago, we had some snow; possibly first time truck has ever been in snow. I started the truck before daylight to let it warm up and also turned the parking lights on so I could see the gauges. Not long after, I smelled something burning and found two wires melted behind the headlight switch.
Larger plug: Pin #10 - Tan/White - Park lamp relay
Larger plug: Pin #12 - Brown - Power, exterior lamps
I found fuse #17 (exterior lamps) had a 30amp instead of 15amp so I assume that's why the wires ended up melting. I assume there is further damage in the harness because my dash lights and cab lights now come on with the switch turned off.
I need to get this fixed but not sure what caused it to begin with. More importantly, I need to get the harness from the switch replaced. Is it possible to do so without removing the entire dash? What's the best way to tackle this? Any guidance would be appreciated because the task seems like it will be a bear.
Larger plug: Pin #10 - Tan/White - Park lamp relay
Larger plug: Pin #12 - Brown - Power, exterior lamps
I found fuse #17 (exterior lamps) had a 30amp instead of 15amp so I assume that's why the wires ended up melting. I assume there is further damage in the harness because my dash lights and cab lights now come on with the switch turned off.
I need to get this fixed but not sure what caused it to begin with. More importantly, I need to get the harness from the switch replaced. Is it possible to do so without removing the entire dash? What's the best way to tackle this? Any guidance would be appreciated because the task seems like it will be a bear.
Hotshot
Joined: Jul 2008
Posts: 12,782
Likes: 2,142
From: N.GA Mountains
That ‘headlight switch harness’ is part of the dash wiring harness. Not exactly an easy fix or swap.
There must have been a short or an overloaded circuit to cause this problem. I think that should be addressed first. If the circuit is working now with correct fuse, maybe it’s an intermittent problem? I would look for chaffed wires near the exterior bulbs first and then work my way back down the harnesses to the fuse block.
I know the upfitters did a SUPER hack job on my cab chassis truck when they installed the flatbed. Per SOP, they hacked the main harness to back of truck just behind cab and installed quick splice wire taps in a big bundle then loosely wrapped tape around it to insure it would hold moisture and slowly degrade the now exposed copper in the harness. This lasted about 3yrs before I had issues and lost my temper discovering what they had done and completely re wiring the flatbed and trailer connections.....
There must have been a short or an overloaded circuit to cause this problem. I think that should be addressed first. If the circuit is working now with correct fuse, maybe it’s an intermittent problem? I would look for chaffed wires near the exterior bulbs first and then work my way back down the harnesses to the fuse block.
I know the upfitters did a SUPER hack job on my cab chassis truck when they installed the flatbed. Per SOP, they hacked the main harness to back of truck just behind cab and installed quick splice wire taps in a big bundle then loosely wrapped tape around it to insure it would hold moisture and slowly degrade the now exposed copper in the harness. This lasted about 3yrs before I had issues and lost my temper discovering what they had done and completely re wiring the flatbed and trailer connections.....
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8th Gear
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I still don't have parking/running lights but I've yet to find the trouble spot. It was my thinking that maybe the snow had caused the short somewhere. I do have a service bed so there could be a mess of wiring in it which I haven't discovered yet.
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8th Gear
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Can someone confirm if the tan/white wire goes directly from the switch to the fuse panel? It appears so but just wanted to make sure.
Also, anywhere I can find new terminals/pins for the connectors? Is that a dealership only item?
Also, anywhere I can find new terminals/pins for the connectors? Is that a dealership only item?
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