Factory Switch to Control Air Lockers – Part 1

Apr 17

Drivetrain, Electrical, How-To, How-To Drivetrain

Article by: RobRed

Applicable Models: 1998 – 2007 / 100 Series Land Cruiser or Lx 470

Updated: 5/2/2014 (updated diagram)

I’m planning to add on-board air and air actuated differential lockers to my 2000 Land Cruiser. In Part 1 of this writeup I’ll be setting up all of the electrical connections and prewiring for the on-board air compressor. Part 2 cover adding a Combination Meter indicator light for Air Compressor. Part 3 will cover mounting the air compressor, connecting the electrical from Part 1 and readying the system for air locker install. Part 4 and 5 will cover the options for front locker interrupt during reverse and disabling ATRAC when the lockers are actuated.

So you want install ARB Air Lockers in your Land Cruiser but you really hate those ugly, bulky ARB switches. You want something slick and factory looking. No problem, simply swagger into your nearest Toyota parts counter and order up some goodies. Ordering a Differential Switch from an 80 Series Land Cruiser along with a FJ Cruiser Aux Light Switch and some misc wire harness parts will give you that factory, sexy look and provide control to the ARB Compressor and lockers.

With this setup you can activate the compressor independently (air up tires etc), engage rear locker or engage rear plus front lockers (the OEM Toyota switch doesn’t provide the ability to lock front only). In our example the locker solenoid will not engage unless the compressor is active, which is, I believe, the way you want it. In addition to the basic switch setup and wiring I will cover using an existing “Dirty Air Filter” dash indicator to show when the compressor is powered up. This is an optional step and requires disassembly of the instrument cluster.

ARB includes a wiring harness in their kits and you can integrate these steps into the ARB harness for your own custom solution, this configuration or any combination of the two. It’s your custom mod. For clarity I’m assuming for the purposes of this writeup that no ARB harness exists. I’m also assuming that you have mounted the compressor, manifolds and other equipment that makes the lockers work.

Before you begin any modification to your vehicle you should fully understand what you are doing and make sure you have the skills to complete the job. TLCFAQ nor it’s authors, commentors or contributors accept any responsibility, or liability for any mishap or problems from any materials posted on the website. Any and all of this can cause serious damage to you or your vehicle. Always consult a qualified professional. I’m Serious. Do this at your own risk.

Major Parts You’ll Need for This Mod:

Differential Switch: Toyota 84725-60020 (80 Series F/R)
Male Connector: Toyota 90980-10631
Wire Splices (x3): Toyota 82998-12170 (165mm long)
FJ Cruiser Aux Light Switch: Toyota PT-297-35070-AS
Wire Harness: Toyota PT-297-35070-SH
High Current Relay (30-80A depending on compressor need)
Bosch Relay 332 209 150 or equivalent (optional for using the cluster light mod)
Hella or equivalent inline ATO fuse holder with ATO Fuse; 10A
16-18awg Terminal block, 1 in, 3 out
Blue Sea Systems 285 series 80A Breaker OR High Power inline fuse
4awg Battery Cable (running from battery to breaker (fuse), breaker (fuse) to compressor replay input, compressor ground, and compressor relay output to compressor power input) You’re compressor may be supplied with appropriate wiring – this could be optional.

The above list is suggested. Your choices and customization is up to you. You will also need, of course, a compressor, manifolds, solenoids and lockers for the final assembly. Depending on your equipment you may have to vary the above suggested list. Regarding the Male Connector and 3 wire splices, you may not need them. My 2000 had the connector wired up to the harness in the dash. If you have the same you could easily harvest that from your existing harness and save $25-40.

The system I will be installing in my Land Cruiser is all ARB, but you could certainly use whatever components you choose:

ARB RD 131 Front Locker
ARB RD 152 Rear Locker
ARB CKMTA12 High Output Compressor
ARB 171503 Manifold Kit

Getting Started:

The FJ Cruiser Aux Light Switch has two bulbs in it. One for the cabin back light and one for the active indicator. As it comes from Toyota the back light is orange and the active is green. My 2000 Land Cruiser has green back lighting through out the cabin so the first thing I did was swap these bulbs. Now the new switch matches the back lighting color and the active indicator will be orange. The bulbs are available to purchase from Toyota so you could find any available colors you like for your switch. Simply give the bulbs (two white discs in the photo below) a gentle quarter turn. They will fall right out. Swap the positions and you are done.

The FJ Aux Lamp switch is a perfect fit in the blank above the differential lock switch. You won’t need to modify the switch body unless you want the switch orientation 180 degrees or in another location. If that’s the case you will need to modify the switch housing slightly by grinding off a small ridge of plastic (see red arrow in the photo below) to allow it to fit in another orientation in the 100 series switch hole.

In the wiring configuration I designed I wanted make the compressor active separately to use tools or air up tires, and to prevent the differential lock switch from activating the locker solenoid unless the compressor was active. You will see in my diagram that the locker switch receives it’s power from the compressor relay output thus preventing premature solenoid activation. Additionally the “compressor” switch indicator also receives it’s active indicator power from the same output. If the solenoid doesn’t activate you wont see the switches indicator come on. If you are doing the cluster mod that indicator wont activate unless the compressor solenoid activates either.

Diagram Updated 5/2/2014

The Aux switch, Diff Locker switch and the ARB solenoids don’t draw much current so no need to use relays for them but I like fuses for safety. You can use an individual fuse holder or a multicircuit fuse block but you only need one circuit. I’m using a Hella single inline fuse holder with a 10A fuse. You will be running a total of 4 wires back into the cockpit from the engine bay; blue, green, yellow and red.

Let’s start in the cockpit:

Remove the cluster finish panel (under the cluster, above the steering wheel)
If you are doing the optional Cluster indicator light remove the instrument cluster
Remove the hood latch and fuel door levers on the lower driver kick panel, 2 screws each
Remove the drivers lower kick panel, 1 screw and 5 clips
Disconnect the various harnesses attached to the kick panel
Remove the switch panel blanks for the Diff Locker and the switch above. If you have an RSCA switch you can remove the blank to the left of the Diff Lock switch location
Insert the Differential Locker switch and Aux Lamp Switch (your compressor switch) in the drivers switch panel. They should snap right in.

In the engine compartment:

Disconnect your main battery negative terminal
Mount your Compressor relay
Mount your Circuit Breaker or High Power Fuse block
Mount your inline fuse holder if needed. This may not be appropriate for your fuse holder type.
Terminate and connect a length of 4awg cable to your compressor relay output (30) and connect to your compressor power input.
Terminate a Ground to your compressor relay (85)
Locate a suitable ACC/Igintion 12v connection point and terminate one 16-18awg wire to the input of your fuse holder (red wire).
Terminate one 16-18awg wire to the output of the fuse holder (red wire). This needs to run back to the cockpit.
Terminate one 16-18awg wire to the trigger input (86) on your compressor relay. Terminate the the other end to the output of the compressor limit switch (blue wire).
Terminate one 16-18awg wire to the compressors Pressure Limit Switch input (blue wire). This needs to run back to the cockpit.
Terminate one 16-18awg wire to the positive (12v) trigger input of your rear locker solenoid (green wire). This needs to run back to the cockpit.
Terminate one 16-18awg wire to the positive (12v) trigger input of your front locker solenoid (yellow Wire). This needs to run back to the cockpit.
You should have four wires to run back to your switch area. Run them through the fire wall at one of the factory entry points and position the ends in the area of the switches.

Back in the cockpit:

Mount your 1×3 terminal block behind the switch area where convenient.
Terminate the red wire to your 1×3 terminal block input.
Cut down the Aux Lamp Switch Harness (PT297-35070-SH) to an appropriate length and strip the 6 wires
Terminate each of the 6 wires from the harness to the appropriate wire you just brought in and surrounding circuits
- Pin 1 (R-L): Active indicator 12 volt input. Gets one of the return outputs from the 1×3 terminal block
- Pin 2 (B): Ground I would tap the Quarter Window switch next to your new Compressor switch to provide this, , white-red wire (W-R).
- Pin 3 (G-R): 12 Volts from a fused Ignition Source. I would tap a nearby circuit, next to your new Compressor switch to provide this. The red-blue wire (R-L) from the Power Quarter Window switch is perfect for this.
- Pin 4 (R-G): 12 volt switched output Connects to the the trigger input on the Compressor relay (blue wire you just brought in from the engine bay)
- Pin 5 (Br): Ground I would tap the Quarter Window switch next to your new Compressor switch to provide this, , white-red wire (W-R).
- Pin 6 (V): 12 Volts via the dash illumination circuit. I would tap the Quarter Window switch next to your new Compressor switch to provide this, green wire (G).
Insert the terminal ends of the three wire splices (82998-12170) in the the connector (90980-10631) at pins 2, 4 and 5
Strip and terminate your Differential switch wires to three of the ones you just brought from the engine bay
- Pin 4: 12 volt input Gets one of the outputs from the 1×3 terminal block (red wire)
- Pin 1: 12 volt output Gets the rear locker trigger from the engine bay (yellow wire)
- Pin 2: 12 volt output Gets the front locker trigger from the engine bay (green wire)
If you are doing the optional cluster indicator you should have one terminal left from the 1×3 terminal block, this is reserved for the coil input of our Bosch relay to control the dash indicator in the cluster. See supplemental wiring diagram in part 2.

Back to the engine room:

Terminate and connect a length of 4awg cable to the output of the Circuit Breaker or high power fuse, terminate the other end to your compressor relay input terminal (87a)
Terminate and connect a length of 4awg cable to the Circuit Breaker or high power fuse input. Terminate and connect the other end of the 4awg cable to the battery positive terminal
Terminate and connect a length of 4awg cable to the compressor ground and terminate the other end on the battery negative terminal.
Install your high power fuse into the block or reset your circuit breaker
Install one 10A fuse in the inline fuse holder you installed
Reconnect your main battery negative terminal

Back in the cockpit:

Plug the Compressor switch harness (PT297-35070-SH) into the Aux Lamp (compressor) switch (Pt297-35070-AS)
Plug the differential switch harness plug into the switch
Make sure the truck is in Park and the Parking Brake is set.
Start the truck and let idle
Depress the Compressor switch, you should hear the compressor power up and the active light in the switch should illuminate
Switch the lockers and make sure they are engaging
With the lockers still engaged switch off the compressor, the lockers should disengage
Reset your locker switch to normal and turn off the car.

If you are not doing the optional cluster indicator, Front Locker Reverse Interrupt or ATRAC interrupt, go ahead and button it up by replacing the kick panel and cluster trim. You are done with part 1.