what are the 'non powered' aux circuits for?

They are not actually complete circuits. It's really just pre-run wiring.

There are 6 circuits in the Bronco connected via relays in the battery box to the battery that are controlled by the the Aux switches inside the Bronco. All six of those terminate over by the fuse box and have heat shrink on them. Then there are 5 additional unconnected wires that run throughout the Bronco

• (1) Fuse box to front grille
• (2) Fuse box to passenger kick panel
• (1) Passenger kick panel to top of windshield near passenger visor
• (1) Passenger kick panel to right-hand quarter panel

The thought is you connect one of those 6 powered circuits to the non-powered circuits run throughout the Bronco to achieve what you are looking to do. So say, for example, that you want to connect a light bar mounted on the top of your Bronco to Aux 5. Aux 5's line is the blue/orange cable on the powered circuits. The non-powered circuit that runs to the top of the windshield is a gray/orange cable. And the non-powered circuit that runs from the fuse box is a brown/white line. So you simply connect the blue/orange cable to the brown/white cable to the gray/orange cable, and bam... you have power to the top of your Bronco by the passenger visor that can be used to power a light bar.

User manual pages 458-460 explain the aux switches. You can download the manual from ford under your account. You can view the manual from your screen in your bronco. You can see it HERE

The Bronco owner's manual (the glove box size version ) is available for purchase through Ford or online resources such as Ebay Motors and other internet sources. I thought about printing the manual myself but my printer would probably have exploded printing that many pages - not to mention the cost of the ink. For me, I much prefer the idea of having a hard copy of the manual instead of the necessity of viewing it on the navigation screen in the vehicle. I purchased my 2021 owner's manual at Ebay Motors.

man, I'm getting tired of having to re-write my responses because the forum logs me out unexpectedly.

Anyways - I think things are finally connecting for me (pun intended) about the pre-run wiring. I was thinking that you HAD to connect one of the wires on the firewall side to the wires on the fusebox side to complete a circuit. It just dawned on me that you can connect your device/lights directly to the terminated/capped wire on the firewall side, if you don't want to use one of the pre-run wires. My only other question is regarding the yellow wire for the 30A switch - from my understanding, a 30a load on a 12v system should require an 8AWG wire - the yellow one doesn't look much (any?) thicker than all the lower amp circuits... is that ok?

Calgecko

man, I'm getting tired of having to re-write my responses because the forum logs me out unexpectedly.

Anyways - I think things are finally connecting for me (pun intended) about the pre-run wiring. I was thinking that you HAD to connect one of the wires on the firewall side to the wires on the fusebox side to complete a circuit. It just dawned on me that you can connect your device/lights directly to the terminated/capped wire on the firewall side, if you don't want to use one of the pre-run wires. My only other question is regarding the yellow wire for the 30A switch - from my understanding, a 30a load on a 12v system should require an 8AWG wire - the yellow one doesn't look much (any?) thicker than all the lower amp circuits... is that ok?

Great question. I'd like to know that also.

Calgecko

man, I'm getting tired of having to re-write my responses because the forum logs me out unexpectedly.

Anyways - I think things are finally connecting for me (pun intended) about the pre-run wiring. I was thinking that you HAD to connect one of the wires on the firewall side to the wires on the fusebox side to complete a circuit. It just dawned on me that you can connect your device/lights directly to the terminated/capped wire on the firewall side, if you don't want to use one of the pre-run wires. My only other question is regarding the yellow wire for the 30A switch - from my understanding, a 30a load on a 12v system should require an 8AWG wire - the yellow one doesn't look much (any?) thicker than all the lower amp circuits... is that ok?

tommygraham

Great question. I'd like to know that also.

All of the powered Aux wires connect to a fuse and/or relay under the hood in the fuse panel. As I understand it, the wire simply acts as a trigger to activate the relay which powers the circuit.

Calgecko
man, I'm getting tired of having to re-write my responses because the forum logs me out unexpectedly.

Anyways - I think things are finally connecting for me (pun intended) about the pre-run wiring. I was thinking that you HAD to connect one of the wires on the firewall side to the wires on the fusebox side to complete a circuit. It just dawned on me that you can connect your device/lights directly to the terminated/capped wire on the firewall side, if you don't want to use one of the pre-run wires. My only other question is regarding the yellow wire for the 30A switch - from my understanding, a 30a load on a 12v system should require an 8AWG wire - the yellow one doesn't look much (any?) thicker than all the lower amp circuits... is that ok?

It depends entirely on how long the run is and the type of load. If you are making a 10+ foot run to the rear of the vehicle or you are powering a compressor that will have a high-power draw... then yea... you'll absolutely want an 6/8-gauge wire. If you have a short 6 inch run to a component that only surges to ~25 amps every now and then... then yeah... the wire they have is fine. If I am being 100% honest, I would have liked to see at least 12-gauge wire on the 30-amp line... because you know someone out there is going to do something dumb and catch their Bronco on fire. But... at the same time, when you are installing aftermarket gear there is a certain level of responsibility you should have towards what you are doing, and what Ford provided isn't the end of the world.

But to be clear... if you are running something like an on-board compressor, you should run power lines for that device directly to the battery with its own independent fuse, and use a relay connected to the Aux lines to turn on/off the compressor. Don't power it from the Aux lines themselves.

Bschurr
All of the powered Aux wires connect to a fuse and/or relay under the hood in the fuse panel. As I understand it, the wire simply acts as a trigger to activate the relay which powers the circuit.

You are correct. The switches themselves control relays in the battery junction box. That relay controls whether the aux line is on or off.

Also, advice, be smart on your switch usage. If you install 2 POD lights that pull only 5 amps, dont waste your 30 amp circuit on it. Its fine to use it as far as function, but why waste your high power circuit when not needed.
Any electrical device will have the full load current rating, use this as a guide to determine which swtich you actually want to use.
Someplace sells the aux switch labels so you can remember which switch is which....

Xpathf1nderX

Also, advice, be smart on your switch usage. If you install 2 POD lights that pull only 5 amps, dont waste your 30 amp circuit on it. Its fine to use it as far as function, but why waste your high power circuit when not needed.
Any electrical device will have the full load current rating, use this as a guide to determine which swtich you actually want to use.
Someplace sells the aux switch labels so you can remember which switch is which....

Stickerfab dot com sells the stickers to label your aux swiches.

There is a lot of confusion with this topic. I made this video to help.