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As someone who spent a couple of hours on experiments with ARB wiring diagram and 4x4TruckLEDs' instruction which is simple says "go figure with the vendor" I have to admit that both did a pretty good job of puzzling single brushless compressor owners.

I still need to find time to put together the final diagram I ended up with. For now, you need only the first, longest, harness. Then connect +(thick red-white wire + fuse), ground (thick black-white wire), and connect the thin red wire at the end of the harness marked as "isolation switch" to whichever AUX switch wire you want.

If you are using the ARB switch alone or in series with you AUX switch (like in my setup), you need to run the thin red wire through the pins 3 and connect its pin 2 to +12V or to your favorite AUX switch

Of course, don't forget to install the pressure switch and connect as well, see the original diagram on arb site https://store.arbusa.com/content/CKBLA12 INST.pdf

The rest of the wires on the harness can be safely removed or taped off.
The single brushless installs the same way at the twin.

Power connects to the battery (fuse first, then battery). Ground goes to the ground (any grounding point on the chasis or your negative terminal, whatever you prefer). To turn the compressor on... the red wire off the 4 wire bundle goes to the upfitter. Done.

Pressure switch just screws in and plugs into the 2 wires ARB gave you, which are already pre-terminated with the connector on it. Just plug it into the pressure switch.

If you try and follow the ARB booklet you will confuse yourself, as it's designed for ALL applications including lockers. For the Broncos... it's really pretty basic/simple.
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The single brushless installs the same way at the twin.

Power connects to the battery (fuse first, then battery). Ground goes to the ground (any grounding point on the chasis or your negative terminal, whatever you prefer). To turn the compressor on... the red wire off the 4 wire bundle goes to the upfitter. Done.

Pressure switch just screws in and plugs into the 2 wires ARB gave you, which are already pre-terminated with the connector on it. Just plug it into the pressure switch.
Yes, I know that now. Please fix your instructions because it is confusing. It talks about twins and ends with something like "for single setup go to arb".

Also, ARB diagram is for more comprehensive setup that most of Bronco6 users actually don't need. The harness also may be improved for Bronco6 but I understand that this will probably never happen.
 

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Yes, I know that now. Please fix your instructions because it is confusing. It talks about twins and ends with something like "for single setup go to arb".

Also, ARB diagram is for more comprehensive setup that most of Bronco6 users actually don't need. The harness also may be improved for Bronco6 but I understand that this will probably never happen.
what’s your order number with us so I can check what we sent you
 

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what’s your order number with us so I can check what we sent you
My order is #43120 but I am good now. The instruction I received is the same as someone posted here several messages above.

The simplest fix is to add the following:

"The single brushless installs the same way at the twin."

phrase into your instruction.

You may want also to cover the arb switch wiring but this is a separate issue.
 

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Yes, I know that now. Please fix your instructions because it is confusing. It talks about twins and ends with something like "for single setup go to arb".

Also, ARB diagram is for more comprehensive setup that most of Bronco6 users actually don't need. The harness also may be improved for Bronco6 but I understand that this will probably never happen.
So, I finally installed my single brushless compressor and wanted to share some details about my setup: KR Offroad mounting bracket and an ARB isolation switch mounted on the bracket under the hood, connected to AUX6. The idea behind having two switches is to be able to turn the compressor off from the driver’s seat.

I found the ARB harness and wiring diagram to be confusing and overcomplicated for an average setup. After reading through this forum and watching a bunch of YT videos, I realized I’m not alone. So after speaking with ARB support, I created my own wiring diagram and simplified the first part of the ARB harness quite a bit. Hopefully it helps someone.

Ford Bronco ARB Brushless Single Compressor Install arb compressor wiring


Please use this at your own risk. The diagram has not been reviewed or approved by ARB.

I’ve also included a couple of photos of the final setup.

Ford Bronco ARB Brushless Single Compressor Install arb1

Ford Bronco ARB Brushless Single Compressor Install arb2


(edit for missed attachment)
 

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Thank you for providing a simple diagram. Do you think the Aux 6 switch and wiring will handle the amps for the compressor. I planned to have one of the Aux switches control a relay that is capable of more amps.

I see there are two wires going into the ARB Harness #1 from the battery. Does that eliminate the need for a relay on the Aux switch?

I have no need for an isolation switch so I can eliminate that.
 

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Thank you for providing a simple diagram. Do you think the Aux 6 switch and wiring will handle the amps for the compressor. I planned to have one of the Aux switches control a relay that is capable of more amps.

I see there are two wires going into the ARB Harness #1 from the battery. Does that eliminate the need for a relay on the Aux switch?

I have no need for an isolation switch so I can eliminate that.
Aux 6 sends current to the compressor control wire. The current there is minimal, sub-amper, I believe (I can measure it if needed), so it should be perfectly fine to use any of the aux switches.

The compressor motor itself is powered separately through the RED-WHT and BLK-WHT wires. The fuse there is 60A.

Part of my initial confusion came from the fact that the ARB harness is not just a coil of wires with sockets. It also contains electronics ("relay") that monitor the pressure switch, turn on/off the compressor motor through the control wire, and beeps error codes.

It appeared that the ARB isolation switch is also a bit smarter than just a simple switch. It has backlight with deeming support and the "relay" can send error codes through the switch LED. I didn't really need both of these features.
 

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Great. Thanks for the explanation. That eliminates having to install a separate relay.

Now , I just need to wait for mine to arrive.
 

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I am finally beginning the install of my single brushless ARB compressor. I have noticed most are installed with the filter toward the front with the air port at the rear. When I got mine laid out, I did it with the filter at the rear and the air port at the front. I like it that way. It is much like that way mcseem installed his but mine has the air tank and port on the opposite side (passenger side) of the compressor.

Is there any advantage to how the air compressor and air port is oriented? I know everything must clear the hood but I will figure that out once I get everything in place. I am using the JCR Offroad mounting bracket, but that doesn't appear to make any difference. I do have to drill my own mounting holes but hat is easy.
 

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I found this thread: https://www.bronco6g.com/forum/threads/arb-single-compressor-install-video-helpful-hints.71700/

which details the install of the BRUSHED compressor SINGLE, but i bought the BRUSHLESS compressor... I have the dual BRUSHED compressor in my van, so I have a little comparison between the two...

I wanted to post a few points on the install of the BRUSHLESS (because of some form factor differences between the brushed and brushless single compressor) that are a little different than the BRUSHED compressor.

1. I went with the single compressor not because it was a little cheaper but because I figured I didn't need the faster fill rate but rather wanted to be more economical with space inside the engine bay. Wrong. The mount basically occupies the space whether it's Double or Single. So don't let that bug you much. Trivial point my dual brushed compressor SOUNDS much better than the single brushless. The single brushless sounds strained and high pitch, but works fine.

2. The install is pretty straightforward. I loosened that inside shock mount bolt quite a bit and it was pretty easy to slip the medial bracket underneath there with it that loose(but not too lose). Torqued it up to spec with torque wrench (if you don't have one of these and have bikes or cars you work on, get them. I have a small 0-20lb/ft and a large 10-90lb/ft torque wrenches.)

3. The only way I could get the configuration of the compressor to fit is fully on its side in this configuration.

IMG_2450.webp


4. I got a little lucky because you need to mount the ARB bracket to the KR off road bracket first without really knowing how the compressor will fit in there. If you mount the ARB bracket too far to the side of the passenger wall, then the pressure control port will hit the KR bracket on the engine side and you can't rotate the compressor "sideways" enough. But if you mount it TOO far to the engine side then it seems it gets in the way with the wiring harnesses near the engine. I would say favor mounting the ARB bracket somewhat but not all the way to the engine side of the KR mount.

IMG_2446.webp


5. I ran the wiring harness and + power along the firewall and had JUST enough positive wire to reach the battery... ( not my cleanest wiring job in the world but it works).

IMG_2479.webp
IMG_2478.webp


6. My dog really laid down on the job on this install..."can you pass the wrench..."[no response from dog]

IMG_2444.webp
For comparison, here's how the original single looks on the 4x4LED bracket, rotated to fit. Been in there 4 years.
I found this thread: https://www.bronco6g.com/forum/threads/arb-single-compressor-install-video-helpful-hints.71700/

which details the install of the BRUSHED compressor SINGLE, but i bought the BRUSHLESS compressor... I have the dual BRUSHED compressor in my van, so I have a little comparison between the two...

I wanted to post a few points on the install of the BRUSHLESS (because of some form factor differences between the brushed and brushless single compressor) that are a little different than the BRUSHED compressor.

1. I went with the single compressor not because it was a little cheaper but because I figured I didn't need the faster fill rate but rather wanted to be more economical with space inside the engine bay. Wrong. The mount basically occupies the space whether it's Double or Single. So don't let that bug you much. Trivial point my dual brushed compressor SOUNDS much better than the single brushless. The single brushless sounds strained and high pitch, but works fine.

2. The install is pretty straightforward. I loosened that inside shock mount bolt quite a bit and it was pretty easy to slip the medial bracket underneath there with it that loose(but not too lose). Torqued it up to spec with torque wrench (if you don't have one of these and have bikes or cars you work on, get them. I have a small 0-20lb/ft and a large 10-90lb/ft torque wrenches.)

3. The only way I could get the configuration of the compressor to fit is fully on its side in this configuration.

Ford Bronco ARB Brushless Single Compressor Install IMG_2450


4. I got a little lucky because you need to mount the ARB bracket to the KR off road bracket first without really knowing how the compressor will fit in there. If you mount the ARB bracket too far to the side of the passenger wall, then the pressure control port will hit the KR bracket on the engine side and you can't rotate the compressor "sideways" enough. But if you mount it TOO far to the engine side then it seems it gets in the way with the wiring harnesses near the engine. I would say favor mounting the ARB bracket somewhat but not all the way to the engine side of the KR mount.

Ford Bronco ARB Brushless Single Compressor Install IMG_2446


5. I ran the wiring harness and + power along the firewall and had JUST enough positive wire to reach the battery... ( not my cleanest wiring job in the world but it works).

Ford Bronco ARB Brushless Single Compressor Install IMG_2479
Ford Bronco ARB Brushless Single Compressor Install IMG_2478


6. My dog really laid down on the job on this install..."can you pass the wrench..."[no response from dog]

Ford Bronco ARB Brushless Single Compressor Install IMG_2444
For comparison, here's how my original ARB single fits on the 4x4LED KR bracket. It's been in there about 4 years.

Ford Bronco ARB Brushless Single Compressor Install 20260327_134011


Ford Bronco ARB Brushless Single Compressor Install 20260327_134042
 

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Damn look at that OG 4x4TruckLEDs.com sticker - We haven't made those in years!
 

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Read through all this and curious why all you chose under the hood vs the tailgate with AAL kit? Thanks
 

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Read through all this and curious why all you chose under the hood vs the tailgate with AAL kit? Thanks
Under the hood is MUCH easier to install. Also you can't install a brushless on the AAL, as it only supports the non-brushless.

Did I mention under hood is easier to install? I've installed the AAL kit for a customer of mine. First and last time too, no matter what you pay me. It was so difficult to install as it barely fit in there. And even once we got it in, the wiring shorted out because there's no room and we had to re-do it and wrap EVERYTHING. The switch wires are exposed on the back so you need to wrap up the switch as well once you insert your wires. And then as I said.... real PITA to install.

I love the idea, really wish it would fit better so we could offer it to customers, but as a retail shop (as we also run a retail shop where we install things) it was SUCH a hassle to install. I think we saw the customer 2-3 times because the kit was missing brackets the first go around (hey that happens).

Also for $24 more you can get the engine mounted compressor bracket which works with ALL ARB Air Compressors (single/twin, brushless, non-brushless) which also means you can run a larger compressor (twin). Although if you get the AAL powder coated it costs more then the engine bay bracket.

So it's a great idea but I think it needs a little tweaking as the ARB air compressor is kind of big to fit in that opening.

For rear mounted air compressors we're a fan of the AGS one. It installs behind the spare tire and gives you a nice internal junction for your switch/compressor.

Engine Mounted Kit: https://www.4x4truckleds.com/kr-off-road-air-compressor-engine-bay-kit-for-2021-ford-bronco/

Spare Tire Mounted Kit w/Optional Interior Panel: https://www.4x4truckleds.com/ags-tire-carrier-kit-for-arb-twin-air-compressor-for-2021-ford-bronco/
 

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Under the hood is MUCH easier to install. Also you can't install a brushless on the AAL, as it only supports the non-brushless.

Did I mention under hood is easier to install? I've installed the AAL kit for a customer of mine. First and last time too, no matter what you pay me. It was so difficult to install as it barely fit in there. And even once we got it in, the wiring shorted out because there's no room and we had to re-do it and wrap EVERYTHING. The switch wires are exposed on the back so you need to wrap up the switch as well once you insert your wires. And then as I said.... real PITA to install.

I love the idea, really wish it would fit better so we could offer it to customers, but as a retail shop (as we also run a retail shop where we install things) it was SUCH a hassle to install. I think we saw the customer 2-3 times because the kit was missing brackets the first go around (hey that happens).

Also for $24 more you can get the engine mounted compressor bracket which works with ALL ARB Air Compressors (single/twin, brushless, non-brushless) which also means you can run a larger compressor (twin). Although if you get the AAL powder coated it costs more then the engine bay bracket.

So it's a great idea but I think it needs a little tweaking as the ARB air compressor is kind of big to fit in that opening.

For rear mounted air compressors we're a fan of the AGS one. It installs behind the spare tire and gives you a nice internal junction for your switch/compressor.

Engine Mounted Kit: https://www.4x4truckleds.com/kr-off-road-air-compressor-engine-bay-kit-for-2021-ford-bronco/

Spare Tire Mounted Kit w/Optional Interior Panel: https://www.4x4truckleds.com/ags-tire-carrier-kit-for-arb-twin-air-compressor-for-2021-ford-bronco/
Great information. Thank you!
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