How do I run a thick cable from windshield light bar into engine bay?

[cbrenthus]

I’m installing an emergency light bar and need to run a very thick cable from the top of the windshield into the engine bay. I was hoping to just run it down the windshield and under the hood, but it’s way too thick for that.

The cable has two thick wires for power and ground, I’d say 10 to 12 gauge, and then nine signal wires which I would say are thinner like 16 to 18 gauge. Put altogether results in a cable about 3/4 of an inch wide.

does anyone have any thoughts on how I can run it into the engine department? My best thought currently is to run it down the side of the windshield and then down the fender and underneath up.

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[V1Rotate]

Your two choices are inside the A pillar or using this guy. You pick how much work you want to put forth.

That said where I would have it coming out of the interior of the A pillar and above the windshield (the way I did/would do it) you’ve got covered up with that bracket that mounts your FD/PD looking light. The custom bracket I made for my light bar/roof rack doesn’t clog that entire hole. Can’t tell if yours does or if you’d just need to drill a hole in it. You see how big a PITA going that way can become but its clean

https://www.kchilites.com/universal...vb-vdAReHIxVEyPR8bZOpfn0HvFY6GaQaAhDeEALw_wcB

 

[adam1991]

Is that the cable that came with the light?

I'm curious--what are the power specs for the light bar? LEDs don't take THAT much power. 10 gauge? That's huge.

 

[GrumpyVet]

Use the accessory wire already installed.

 

[Dantastic]

Use the accessory wire already installed.

I wouldn’t use that if the light he has is packing a gauged wire as big as it looks. Shoot most light bars are too much for that pre-wire.

 

[Brian_B]

There is an aftermarket installation guide floating around the site here somewhere, and it shows exactly where in the rubber trim along the top where you should run cables. There's a pre-notched place in the rubber where you can run the cable through.

I'm not familiar enough with it to say exactly where, just that it's outlined very well in that installation guide and that it does exist.

 

[cbrenthus]

Is that the cable that came with the light?

I'm curious--what are the power specs for the light bar? LEDs don't take THAT much power. 10 gauge? That's huge.

Yes, it is directly wired into the light bar. The main +/- cables might not be 10 gauge, but they are thicker than your average wire. The total light bar including signal wires requires a 20 amp fuse, and just the power is 15. Granted, that is the fuse and not the static power draw, but still. The light bar has many functions, many of which can be used at the same time. Could have takedowns and alley lights on, flashing emergency lights, and a traffic advisor all at the same time!

Use the accessory wire already installed.

I wouldn’t use that if the light he has is packing a gauged wire as big as it looks. Shoot most light bars are too much for that pre-wire.

Yup, I could use that for one of the signal wires, but that's it.

There is an aftermarket installation guide floating around the site here somewhere, and it shows exactly where in the rubber trim along the top where you should run cables. There's a pre-notched place in the rubber where you can run the cable through.

I'm not familiar enough with it to say exactly where, just that it's outlined very well in that installation guide and that it does exist.

I'll take a look, but I think the cable is still too thick to go that route anyway.

I appreciate all the thoughts. Right now I'm thinking I might drill a hole in the plastic cowl next to the mirror, where the accessory mounting point is, and run it that way. Of course I would take the cowl off first and make sure I could run it, and make sure I could buy another cowl. My second thought is to run the cable down the fender and underneath, but hate to put adhesive cable tie bases on the paint. I guess its not worse than emblems, though.

Thank you for all the replies!


Here are the specs:

 

[flip]

Nothing to add but wanted to say Ford needs to come up with a passthrough of some sort. Having to drill or tuck bar light wiring in 2024 is so piker.

 

[KABQ]

To make the harness smaller could you run power/signal down one pillar and ground down the other?

 

[HotdogThud]

To make the harness smaller could you run power/signal down one pillar and ground down the other?

This was my thought too. depending on how long the leads are, you might be able to extend rearward along the roll bar, down the B pillar and along the rocker panel back into the engine bay.

 

[cbrenthus]

To make the harness smaller could you run power/signal down one pillar and ground down the other?

Not a bad idea, I'd probably keep the power/ground together and then run the signal wires separately. Another thought I'm having is to possibly look at a wireless controller, and mount the receiver under the light bar.

 

[4x4TruckLEDs.com]

I’m installing an emergency light bar and need to run a very thick cable from the top of the windshield into the engine bay. I was hoping to just run it down the windshield and under the hood, but it’s way too thick for that.

The cable has two thick wires for power and ground, I’d say 10 to 12 gauge, and then nine signal wires which I would say are thinner like 16 to 18 gauge. Put altogether results in a cable about 3/4 of an inch wide.

does anyone have any thoughts on how I can run it into the engine department? My best thought currently is to run it down the side of the windshield and then down the fender and underneath up.

Use the KC Wire Hider. It's what we use to hide the wires on all of our installs:

https://www.4x4truckleds.com/kc-hilites-universal-wire-hider/

 

[cbrenthus]

Use the KC Wire Hider. It's what we use to hide the wires on all of our installs:

https://www.4x4truckleds.com/kc-hilites-universal-wire-hider/

I appreciate that and might do so to go down the window, but the issue is how I get such a thick cable from outside the vehicle into the engine bay without drilling or making extensive modifications.

 

[Chrome_Pony]

Time for a snorkel kit to hide the wire down the A pillar, it's the only logical way.

 

[4x4TruckLEDs.com]

I appreciate that and might do so to go down the window, but the issue is how I get such a thick cable from outside the vehicle into the engine bay without drilling or making extensive modifications.

You just run it under the cowl...

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