Engine won’t shut off

[Dan Larsen]

Here’s the post-morten. Problem: The after-market lights I installed caused the wiring harness and power distribution box to get overheat, melt wire insulation and cause some kind of overload/short to the system. Attached are photos. About 2 years ago, I installed 3 pair of Rigid Industries LED lights in the front bumper slots on both sides. I believe I wired them correctly to the factory auxiliary switches according to Ford’s wiring diagram and Rigid Industries installation instructions. They worked fine for 2 years, no problems. The night before problem, I used the lights constantly for about 2 hours. The factory auxiliary wires were about 20 gauge, the Rigid about 12 gau ge. Cost: about $2,000 for a new wiring harness, power box and labor. Lesson: Use a relay even when wiring aftermarket lights into the factory auxiliary switches.

 

[CoronaRaptor]

Here’s the post-morten. Problem: The after-market lights I installed caused the wiring harness and power distribution box to get overheat, melt wire insulation and cause some kind of overload/short to the system. Attached are photos. About 2 years ago, I installed 3 pair of Rigid Industries LED lights in the front bumper slots on both sides. I believe I wired them correctly to the factory auxiliary switches according to Ford’s wiring diagram and Rigid Industries installation instructions. They worked fine for 2 years, no problems. The night before problem, I used the lights constantly for about 2 hours. The factory auxiliary wires were about 20 gauge, the Rigid about 12 gau ge. Cost: about $2,000 for a new wiring harness, power box and labor. Lesson: Use a relay even when wiring aftermarket lights into the factory auxiliary switches.

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Damn dude, yeah, i run an additional inline fuse for backup on all my lights. Well, it could of been worse, at least you man'd up and admitted the mistake, hopefully others can learn from this and avoid the same problem. Great post!

 

[wheelman55]

Thanks for the follow up. Lesson learned about using relays.

 

[Droid]

How can it melt without the current draw exceeding the fuse? These are intended to be used exactly the way you had it set up. The interior switches are already wired to an OEM relay, right?

 

[wheelman55]

Likely was due to a combination of small wire gauge of the aux wires, fact that they are in a tight bundle and length of wire run.

Wire ampacity gets de-rated for each of the three reasons above. The combination is the likely cause of the failure.

here’s a list of wire sizes in my 2018 Raptor.

2018 Colors
Aux 1 - Green/White - 15A, 20 awg
Aux 2 - Brown/Blue - 15A, 20 awg
Aux 3 - Gray/Yellow - 10A, 20 awg
Aux 4 - Green/Yellow - 10A, 20 awg
Aux 5 - Brown/White - 5A, 22/24 awg
Aux 6 - Green/Orange - 5A, 22/24 awg

 

[Turning Blue]

I'm probably the last guy who should talk about automotive electrical wiring but I don't understand how simply connecting to wires intended for aftermarket lighting can be the cause? Were they all wired to either wire 5, or wire 6?

Even if they were, as @Droid suggested, isn't there a fuse or relay already built into the system? This sounds like another case of, "Let's blame it on the modifications to earn our dealership more money."

Can anyone guess how many Raptors, including mine, have aftermarket lights installed as designed without melting the harness....yet? And why does Ford use the smallest gauge wires found on the truck for the upfitter switches? I'm not buying their explanation.

There, now that I got that off my chest...Thanks for sharing @Dan Larsen. I feel your pain!

 

[MTF]

I wouldn't trust the OEM micro relays, standard relays are cheap on Amazon!!!
You can then use proper gauge 14, 12 wiring to get the most out off your add-ons.
Takes a few minutes more to add it and use the aux switch to trigger the relay.

 

[CoronaRaptor]

How can it melt without the current draw exceeding the fuse? These are intended to be used exactly the way you had it set up. The interior switches are already wired to an OEM relay, right?

Basically, a lot of installations are using the factory fuse and it is rated higher than the current draw of the operating system (light ex.) , if you are using a current draw lower than the rated protection (factory fuse) you should add a rated fuse inline to protect what you are operating. Also any nick in the wiring which is intermittently shorting out will cause the wiring to overheat, I have seen this time and time again in my field.

 

[GordoJay]

Also any nick in the wiring which is intermittently shorting out will cause the wiring to overheat, I have seen this time and time again in my field.

This is likely the problem. Nicks, damaged or defective wire, bad crimps, all can cause heating. If the current load of the light was less than the switch rating, you wired it correctly, and you were under warranty, it probably should have been fixed under that warranty. I'm hearing that it was your fault because you were dumb enough to use the upfitter switches as advertised. That sounds like stealership BS designed to earn them more money at your expense. So hopefully the OP wasn't under warranty and it's moot.

 

[CoronaRaptor]

This is likely the problem. Nicks, damaged or defective wire, bad crimps, all can cause heating. If the current load of the light was less than the switch rating, you wired it correctly, and you were under warranty, it probably should have been fixed under that warranty. I'm hearing that it was your fault because you were dumb enough to use the upfitter switches as advertised. That sounds like stealership BS designed to earn them more money at your expense. So hopefully the OP wasn't under warranty and it's moot.

That's definitely a good way of looking at it, some of us (very few) have the knowledge and training to not go by the factory directions. I wouldn't say people are dumb to it, but just not educated on wiring procedures and I agree with what you are saying. I wonder if there is anything in the manual that states they should be wired by professionals or not? I always just used the manual for the color codes and never looked further, lol.