5th Gen Mods, Accessories, Install

ARB Twin Compressor Install 5th Gen 4Runner

Updated 10/11/19 / Read Time: 10 mins

ARB Compressor Install - 5th Gen 4Runner

Step-by-Step Installation of ARB Twin Onboard air Compressor on 5th Gen 4Runner with Switch-Pros Harness and M.O.R.E. Bracket

I have been running the Smittybilt 5.7 Air Compressor for a little over a year now. I have no complaints about it.

That compressor has been a workhorse for my tires as well as a few friends after a long day on the trail. It has gone from truck to truck, airing up tires from 33″ – 35″ without a sweat, unlike the Viar 400p compressor that needed to take a break in between airing up 2 33″ tires.

While traditional ground-based air compressors have their place in the off-road world, there are some additional highlights and benefits when it comes to onboard air compressors.

Coming from a traditional air compressor, I always wondered how much better it would be to run an onboard air compressor. I had always been a little hesitant to run an onboard air compressor for a few reasons, including the price and frequency of use…but mainly the price.

For the most part, I never really felt like I “needed” an onboard air compressor…until now.

Why an onboard air Compressor?

Steel Braided Hose

The main reasons I wanted to jump to onboard air were to air up my tires faster, reduce the set-up and breakdown process and free up space.

Benefits of Onboard Air?

  1. Save space in the cargo area
  2. No Compressor set-up and breakdown
  3. Can’t forget the compressor
  4. Air up tires faster
  5. Future ARB Locker ready + tank ready with M.O.R.E bracket

Now, which onboard air compressor to choose? The choice was between the popular ARB twin or single compressor for the obvious reasons of ARB being one of the highest-quality brands in the off-road space.

CKMTA24 (twin) or CKMTA12 (single)?

The output on the Smittybilt 5.7 CFM (cubic feet per minute) air compressor was fine, but ARB packs a slightly higher CFM with a higher duty cycle (60% vs 100%). What is the Duty Cycle?

The ARB Twin (CKMTA24) compressor features 6.16 CFM compared to the CKMTA12 which is about half that (2.8 CFM). These CFM numbers are not always accurate though. The exact CFM will vary depending on the exact PSI load. For example, at a 20PSI load, the 6 CFM compressor may only produce 5 CFM which will take longer to air up than 6 CFM which you would see at a lower PSI load.

Both ARB compressors will work just fine for airing up tires, lockers and even blowing off some dash dust. BUT, the twin packs a larger volume of compressed air in a shorter period of time, which something like air tools (short bursts) can benefit from. But, the compressor alone isn’t going to give your air tools the true performance you want. If your goal is air tools or something that needs shorter bursts of built-up air, then you need to add a 1-gallon tank and the twin is preferred.

Tank or No Tank?

I currently opted for no 1-gallon tank. For starters, a tank isn’t necessarily going to help me air up faster, nor is it going to assist in any of my other current off-road needs. If you are planning on running air tools, you should buy a tank for the reasons mentioned above; more air (CF) in less time (M).

CO2 – PowerTank?

I also thought about going CO2, like a PowerTank but after seeing a few guys handle and mount tanks in the rear cargo area, I thought otherwise as it takes up more space which is what I am attempting to avoid.

I think PowerTanks might be overkill for airing up tires alone. They make a badass product, but I just don’t need to air up my tires in under 2 minutes. I can live with 5 minutes.

If airing up as fast as possible and running air tools is what you are looking for, then go the CO2 route.

Save space with onboard air

The other main reason was to save space in the rear cargo area. I was carrying my Smittybilt 5.7 in the rear cargo area and it was taking up space—and awkward space at that.

I had a recovery box with gear and then a separate bag for the Smittybilt that just got in the way. Also, I am planning a drawer system build in the back and the more I can free up in the cargo area, the better.

Installing the ARB Twin Compressor on the 5th Gen 4Runner

I am running a Switch-Pros 9100 so if you have a Switch-Pros or SPOD, your install will be similar. If you don’t, I will give you an optional route on how to wire the ARB Twin Compressor Switch (because the switch is the only thing different).

NOTE: This install is for airing up my tires only; I will not be using the locker switch wires.

Please read through this install from start to finish before starting as there are many working parts.

Preferred Tools for Installation

ARB Compressor Tools

You may need more tools but this should give you a close idea of what to prepare for.

ARB Compressor Installation Time:

  • 2-3 Hours

Main Products Used Here:

  1. Mountain Off-Road ARB Bracket: Check Price
  2. Switch-Pros Quick-Connect Harness: Check Price
  3. ARB Twin Compressor: Check Price
  4. Extra Small NPT Elbow (male/female): Check Price
  5. Vair steel braided hose: Check Price
  6. Quick-Connect Coupler (male/female): Check Price
  7. MORRFlate: Check Price

Preferred Tools:

  1. Socket wrench
  2. 10mm socket
  3. 12mm socket
  4. Diagonal Cutting Pliers
  5. Open-End wrenches
  6. Small Screwdriver
  7. Plastic Pry Tools
  8. Heat Gun: Check Price
  9. Best Wire Crimps: Check Price
  10. Wire Strippers
  11. Electrical Tape
  12. Wiring Loom
  13. 8 Gauge AWG Ring Terminals: Check Price
  14. 6 Gauge AWG Ring Terminals: Check Price
  15. Scissors
  16. Zip Ties
  17. Alligator Clips

Step 1: Install the M.O.R.E. ARB Twin Bracket

Mountain Off-Road Enterprise ARB Mount

For my install, I am using the Mountain Off-Road Enterprise bracket.

See that ARB compressor bracket install here.

The install of the bracket is pretty simple once you get the parts figured out. Read through that step-by-step install and fully understand how it works before moving forward with wiring the ARB compressor switch and unit.

 Step 2: Prepare the Switch-Pros ARB Harness

Switch-Pros Quick Connect Harness

If you are using a switch panel like an sPOD or Switch-Pros, the Switch-Pros quick harness will work. There is nothing that would change from sPOD to Switch-Pros (in terms of the switch terminal).

If you have an sPOD or any other built-in switch panel system, this harness will work for you as well. Check out our Switch-Pros Quick Connect wiring harness here.

It’s not needed for this install but it may make wiring ARB locker switches easier, should you get there one day.

Step 3: Prepare ARB Wiring Harness

ARB Compressor Wiring Harness Explained

This is what the final ARB wiring harness will look like. Once you connect the Switch-Pros wiring harness to the ARB switch harness, you are good to go. The rest of the install is just running loom and zip ties. Honestly, a very simple install.

I will walk you through wiring the ARB harness from start to finish. There is not much that needs to be done, but if you are looking for a play by play, this should help.

Step 4: Using Locker Switches or No?

ARB Compressor Wiring Harness for Lockers

If you are not using ARB lockers (green and yellow wires), you don’t need this portion of the harness. BUT, in case we ever do add our front/rear ARB lockers, then we will want to save this portion of the harness. Instead of taking the plastic connector clips off and tossing them, we are going to wrap them into some loom and tape it up. If we ever decide to add front/rear or just front lockers (if you already have a rear locker), we can just unpackage this portion of the harness and run a new switch wire.

Step 5: ARB Compressor Wiring Power Wire (Motor Power)

ARB Compressor Wiring Power Wire (Motor Power)

The first portion of the install is simple.

Fan out the stranded wire on both power wires until you have even space between each strand on each wire. Feed the wires into each other, then squeeze and twist the wires together as tight as possible.

Then clip the excess strands off the end so you have a nice smooth straight edge of stranded wire.

Step 6: ARB Compressor Wiring – Power Wire

ARB Compressor Wiring Power Wire (Motor Power)

Use a 6 AWG ring terminal to crimp the wires together. Don’t forget to feed a piece of heat shrink around the two wires before crimping a ring terminal into place.

Step 7: ARB Compressor Wiring – Ground Wire

ARB Compressor Wiring Ground Wire (Motor Power)

You can repeat the same process above with the power wire also for the ground wire.

The ground wire is going to be smaller than the power wire which equates to about an 8 AWG ring terminal. Again, place some heat shrink over the terminal before crimping the terminal into place.

Step 8: ARB Compressor Wiring: Switch Wire (Switch-Pros Quick Connect)

Switch-Pros Quick Connect - to ARB

If you followed our previous post on the Switch-Pros Quick Connect harness, then this is what you should end up with. Connect the SP harness to the ARB harness and done.

Step 9: Optional: Add Wire Loom around provided ARB Wiring Harness

ARB Compressor Harness - Loom

This is what your ARB switch harness (with the locker switches) should look like. The locker switch connects are just wrapped into the wiring loom.

Step 10: Heat Shrink ARB Compressor Harness

Heat Shrink ARB Compressor Harness

The final power and ground wires are wired together and sleeved with some heat shrink. After you shrink the ring terminals and heat shrink down, your power harness should be ready to go.

Step 10 (A): Final Harness

ARB Twin Wiring Harness 4Runner

After your heat shrink is on and terminals have been crimped onto their respective harness, you are ready to run some wires.

Step 11: Testing ARB Compressor Before Wiring

Testing ARB Compressor Before Wiring

Before you start zipping wires into place, it’s always a good idea to test the final wire harness.

Step 12: ARB Twin Compressor Ready to Run Wiring Harness

ARB Twin Compressor Install

Once everything is wired and ready to go, position your wires into place towards the battery first.

I like to run my wires from the battery first and then to the unit so that I can account for extra wiring along the way. Usually, other harnesses are cut to length, but for this install, we are leaving some wiring harness intact for possible future air lockers.

Step 13: Run ARB Wiring Harness Along Firewall

ARb Wiring Harness

Once you have positioned your power and ground cables in place, run the motor and switch harness along with the firewall to the other side of the cab.

Step 14: Extra Wiring Loom

Extra Wiring Loom

With the extra wiring loom you have left, attach them underneath the bracket or behind the bracket to the firewall area along with another factory wiring harness.

Step 15: Connect the Air Compressor Power and Switch

Connect the Air Compressor Power and Switch

Connect your power and switch wires to the ARB compressor and prepare the unit and placement of wires prior to the final install on the M.O.R.E. bracket.

Step 16: Pull Back Weather Strip for Better Access

Optional (pull up Hood Plastics)

You may need to pull back the engine weather stripping in order to get a better handle on the compressor.

Step 17: Position Top Bracket Into Place

Position Top Bracket Into Place

Position the upper M.O.R.E. bracket with the ARB compressor into place on top of the lower M.O.R.E. bracket. Once the top bracket is on the lower M.O.R.E. bracket, you can finally secure them together using the provided M.O.R.E. hardware.

Step 18: Connect Power and Ground

Connect Power and Ground

Lastly, you can connect your power and ground back up and finally test the compressor one last time.

Step 19: ARB quick connect coupling

arb quick connect coupling

I wanted to run the ARB quick connect coupling. Well, it didn’t fit. I tried it every which way and nothing.

I ended up buying the most compact male/female elbow I could find hoping it would clear the ARB compressor plate as I cranked on it with a 19mm. And it cleared.

Step 20: 1/4″ NPT Elbow: Male and Female

Elbow 1/4" Male NPT MPT MIP / 1/4" Female

Step 20 (A): 1/4″ quick connect coupler

1/4" quick connect coupler

I ported a 1/4″ quick connect coupler from Home Depot out the side. The hood barely clears this coupling and elbow.

Step 21: Steel Braided Hose

Steel Braided Hose

I added a Vair steel braided hose and then added another 1/4″ quick connect coupler to connect to my MORRflate.

Step 22: MORRFlate – Testing your preferred trail set up


The final setup will look something like this on the trail. The ARB twin compressor is connected to a steel braided hose which connects to the MORRFlate, which finally runs an ARB EZ Deflator on the end to read the pressure.

With running the MORRFlate, I can deflate all four tires (285/75R17 – 33.8″) from 38PSI to 18PSI in 2:20 (two minutes and twenty seconds), and then air up all four tires from 18PSI to 38PSI in 4:54 (four minutes and fifty-four seconds). Having the MORRFlate is really nice and prevents you from putting stress on your knees while kneeling over at each tire.

I am extremely happy with the new ARB compressor over the previous Smittybilt Air Compressor I reviewed. There are a few big changes in benefits I see by going hard mounted.

Benefits of Onboard Air?

  1. Save space in the cargo area
  2. No Compressor set-up and breakdown
  3. Can’t forget the compressor
  4. Air up tires faster
  5. Future ARB Locker ready + 1-gallon tank ready

I am pretty stoked to finally have this portion of the build complete. Now I can move to the back and start configuring my rear cargo space a little better. But first, I did want to give the PowerTank or CO2, in general, a shot; so I am planning a DIY kit and then I’m going to put that up against the ARB twin to see which one I genuinely like more.

Questions or Comments? Please leave them below!

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Dan Webster
Dan Webster
July 19, 2020 9:04 pm

No issues with dust effecting the compressor under the hood, eh?

Gary Collins
Gary Collins
June 11, 2020 10:07 am

This might be a stupid question, but I’m curious. I see that you’ve installed a fuse system there above the stock fuse box. Why run the ARB compressor directly to the battery? Isn’t that what the fuse system is for?

Gary Collins
Gary Collins
June 11, 2020 11:05 am

Okay, that’s make sense. And another question, why didn’t the ARB quick connect coupling work? You said it wouldn’t fit. What was stopping it?

January 15, 2020 3:56 pm

Brenan, are you running a dual battery setup for your accessories? Or do you get by just fine on the main battery and just keeping the engine on?

January 16, 2020 7:28 am

Okay thanks for the info!

October 16, 2019 11:27 am

Disadvantages of on-board Twin ARB: 1. Loose space under hood, especially space for 2nd battery. 2. If inflation speed is main goal, get the Twin ARB portable version. 3. To take advantages of all the Twin ARB can do for you, where do you install the air tank. 4. Pneumatic locker(s) are probably on very few 4×4 4R folk’s wish list. Breath deeply, this list is just food for thought. I have the Twin ARB with tank installed in my Ford camper van and love it! On my 4R I went with the VIAIR 400P Portable Compressor that I keep… Read more »

October 16, 2019 1:47 pm
Reply to  Coyotearms

Air tank is mounted under the compressor. I have this same setup.

October 17, 2019 4:00 pm
Reply to  Coyotearms

I am running this (almost) same setup and a dual battery system in mine. I relocated the secondary smog pump underneath the compressor. (Does require a different mount. I got it from Bandi on T4R.org) For the time being, I lose a tank. I intend to get a rear bumper and move the spare to the rear. In its place I will install a 3-gallon tank. I want air in the rear, where all the work and storage is anyway. After that, I’ll never have to get under the hood again. Just my $.02.

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