Factory AUX Switch wiring sure seems thin…

[Droz]

So I added some LED lighting to my Bronco and wired up to the factory upfitter switches. No issues. But the factory wiring for the switches seems to be a very small gage wire, like 18ga or less. I always thought when you wired the power to a light you used at least 12ga or better. Is it because LED draw less power? Just looking for a bit of knowledge here. Thanks.

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[heavyD]

Aux 1 & 2 (30A & 15A Fuse): 1.5mm2 (16AWG)
Aux 3 to 6 (10A Fuse): 0.75mm2 (19AWG)

I'm not clear on how they get away with 1.5mm2 for the 30A circuit as that should be in the range of 10AWG typically for a circuit of that amperage.

 

[Scoop]

If the lights you want to install draw more amps than the selected switch is rated for you need to use a relay. The wire size is sufficient for what each switch is rated. Yes, LEDs do typically draw less power.

 

[sklnbnzaz]

Make sure that the amperage rating of the switch you choose is in line with the amperage of your lighting. If you use a relay n and wire it up properly then your upfitter will operate as a trigger for your relay. I am running lights as follows….

1 - 14 amps no relay
2 - 8 amps no relay
3 - 14 amps with relay
4 - 4 amps no relay
5 - 5 amps no relay
6 - 32 amps with relay

 

[4x4TruckLEDs.com]

So I added some LED lighting to my Bronco and wired up to the factory upfitter switches. No issues. But the factory wiring for the switches seems to be a very small gage wire, like 18ga or less. I always thought when you wired the power to a light you used at least 12ga or better. Is it because LED draw less power? Just looking for a bit of knowledge here. Thanks.

You use the proper gauge for the power source. They have a variety of different gauges for the upfitters as each one is a different amperage.

However, with that said, the pass-through wires they leave you I feel are under-sized for anything worthwhile. The pass-through wire at the top of the truck, which they assumed you'd use for a light bar, is WAY TOO SMALL for any real light bar.

 

[CalvinT]

light bar, is WAY TOO SMALL for any real light bar.

Depends on the light bar. I'm considering either the Baja Designs S8 or Hella Black Magic Slim, both 40" long. Either will give adequate light for my purposes. But then I don't race. Factory wiring is sufficient for either one.

 

[4x4TruckLEDs.com]

Depends on the light bar. I'm considering either the Baja Designs S8 or Hella Black Magic Slim, both 40" long. Either will give adequate light for my purposes. But then I don't race. Factory wiring is sufficient for either one.

No light bar that is 40" or higher can use that small wire up there. That wire is only good for maybe 5 amps or under. Any light bar 40" or higher pulls more then that.

We're one of Baja Designs biggest dealers btw, so grab that S8 bar from us. You'll also want harness 64-0094 and the KC Wire Hiders as well.

 

[heavyD]

No light bar that is 40" or higher can use that small wire up there. That wire is only good for maybe 5 amps or under. Any light bar 40" or higher pulls more then that.

We're one of Baja Designs biggest dealers btw, so grab that S8 bar from us. You'll also want harness 64-0094 and the KC Wire Hiders as well.

The 1.5mm2 conductor Ford runs for the non-powered circuits should be able to handle 16A. If the light bar is pulling a larger load, you could local mount the interposing relay near the light bar and run properly sized conductors through the relay contacts to the light. Are these LED light bars really pulling that much current as a standard 2 foot LED industrial fixture these days is only 30-40W.

 

[sklnbnzaz]

Make sure that the amperage rating of the switch you choose is in line with the amperage of your lighting. If you use a relay n and wire it up properly then your upfitter will operate as a trigger for your relay. I am running lights as follows….

1 - 14 amps no relay
2 - 8 amps no relay
3 - 14 amps with relay
4 - 4 amps no relay
5 - 5 amps no relay
6 - 32 amps with relay

In all reality... I really should be running a relay on the up fitter switch 1.

 

[4x4TruckLEDs.com]

The 1.5mm2 conductor Ford runs for the non-powered circuits should be able to handle 16A. If the light bar is pulling a larger load, you could local mount the interposing relay near the light bar and run properly sized conductors through the relay contacts to the light. Are these LED light bars really pulling that much current as a standard 2 foot LED industrial fixture these days is only 30-40W.

That wire is not sufficient to power a 40" light bar.

And if you are going to start running wires for a relay... well why bother? Just run the wire from the powered upfitter up there

A 40" S8 bar pulls 16 amps which is more then that tiny little wire is rated for.

 

[4x4TruckLEDs.com]

In all reality... I really should be running a relay on the up fitter switch 1.

Depending on the light bar you might need a relay. But a Baja Designs 40" S8 is 16 amps, so upfitter 1 is fine for it.

 

[CalvinT]

No light bar that is 40" or higher can use that small wire up there. That wire is only good for maybe 5 amps or under. Any light bar 40" or higher pulls more then that.

I prefer to buy from someone who gives accurate information.

That wire is 1.5m^2 wire. The insulation is rated for 120C and the wire is in a bundle with no cooling.
SAE J1127/J1128 (automotive) @ 85C ambient, ampacity is 15-18A

Both of the light bars I mentioned draw around 16A or less.

https://www.bajadesigns.com/products/s8-white-straight-led-light-bar-universal/?sku=704003WT

https://myhellalights.com/product/black-magic-tough-slim-lightbars/

Do your homework. I do.

 

[4x4TruckLEDs.com]

I prefer to buy from someone who gives accurate information.

That wire is 1.5m^2 wire. The insulation is rated for 120C and the wire is in a bundle with no cooling.
SAE J1127/J1128 (automotive) @ 85C ambient, ampacity is 15-18A

Both of the light bars I mentioned draw around 16A or less.

https://www.bajadesigns.com/products/s8-white-straight-led-light-bar-universal/?sku=704003WT

https://myhellalights.com/product/black-magic-tough-slim-lightbars/

Do your homework. I do.

That 1.5m (about 15 gauge if you do the math) isn't actually "15 gauge". It's more like a 20 AWG wire in reality. Ford's "measurement" is of the entire wire + jacket. But when you look at the wire, it's more like a 20AWG wire.

To properly power a 16 amp circuit that will be located about 10' away you need a 14gauge minimum wire size. (and im being extremely fair at 10', because in reality it's probably more like 15')

Therefore, that wire is NOT sufficient to power a 40" Baja Designs S8 bar.

Don't believe me? You can go pull down your liner a bit and access that wire ford left you. Strip it back, measure it yourself. It's too small of a wire to run 16 amps through.

 

[sklnbnzaz]

No light bar that is 40" or higher can use that small wire up there. That wire is only good for maybe 5 amps or under. Any light bar 40" or higher pulls more then that.

We're one of Baja Designs biggest dealers btw, so grab that S8 bar from us. You'll also want harness 64-0094 and the KC Wire Hiders as well.

I agree... Err on the side of caution ALWAYS when it comes to wiring. Match the fuse to the draw and keep the draw well under the fuse/wire rating. Once you figure out or smell a fire brewing, it will likely be too late. So many people think that they can just throw a bigger fuse in and be fine, just a lack of understanding. The fuse protects the wire, NOT the device. If you put a 30 amp fuse in and have under rated wiring, the wiring will burn before the fuse pops.

 

[sklnbnzaz]

That 1.5m (about 15 gauge if you do the math) isn't actually "15 gauge". It's more like a 20 AWG wire in reality. Ford's "measurement" is of the entire wire + jacket. But when you look at the wire, it's more like a 20AWG wire.

To properly power a 16 amp circuit that will be located about 10' away you need a 14gauge minimum wire size. (and im being extremely fair at 10', because in reality it's probably more like 15')

Therefore, that wire is NOT sufficient to power a 40" Baja Designs S8 bar.

Don't believe me? You can go pull down your liner a bit and access that wire ford left you. Strip it back, measure it yourself. It's too small of a wire to run 16 amps through.

I think what Adam is trying to do here is make sure that other's don't make mistakes and burn their stuff up.

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