DIY: Wire ARB Locker to Disable ABS and turn on dash diff lock indicator

First, thank you to @landphil and @Benson X for providing some of these pictures. I'm only creating another write-up because some people on Instagram asked me to after seeing this mod. I used landphils write up as the base for what I did today, which was wire my ARB locker in my SR5 to illuminate the diff lock light on the dash and disable ABS.

Links to their write-ups:

https://www.tacomaworld.com/threads/4lo-trac-abs-kill-switch-why-why-not.257444/#post-6254094

https://www.tacomaworld.com/threads...-diff-write-up-pics.77649/page-7#post-5324525

I don't know what all trim levels this will work on. I have a 2005 SR5 with no VSC or factory locker.

The meat and potatoes of it are when the green wire is uninterrupted, the ABS is enabled. When you ground the wire that's coming out of the connector, the truck thinks the nonexistent factory locker is enabled, thus illuminating the dash light and disabling ABS. Onto the half-ass writeup.

The first step is to locate the wire. It's the light green wire, pin 4, connector IB1.









The next step is to wire in the relay. I used a standard 5 pin relay.




For pin 86, you can have any +12v trigger the relay. I chose to tap into the yellow wire from my ARB harness. This meant that when I activated my rear locker, the yellow wire became charged, thus triggering the relay.







If you cross some wires like I did today, check IG1 No 2 fuse on the interior fuse panel. I made that mistake today.

https://www.tacomaworld.com/threads/did-i-fry-my-abs-ecu-no-no-i-did-not.718436/


https://youtu.be/PpVUDNLP7KE

 

Great job! And another thing to do!

 

Nice work, I don't believe you have to ground terminal 87 though, have it open and reducing the voltage to EXI2 of the skid control ECU should be sufficient to cause ABS to de-activate. I drew a schematic for what you have done for others benefit. You could do this mod even simpler by eliminating the relay and using a DPDT switch, use the set of NO switch contacts to activate the locker and the other set of NC contacts to open the ABS circuit.







For reference, the TRD offroad accomplishes this by the rear differential lock switch closing and reducing the voltage available to EXI2 of the skid control ECU. The wetting voltage for the offroads is provided by the gauge cluster fuse vs. the IG1 No. 2 fuse for the non TRD offroads. As you figured out, if you ground the fuse side, you get yourself a direct short to ground.

 

I tried simply cutting the wire and it wasn’t enough to disable the abs, it had to be grounded.

 

Interesting, perhaps a difference in skid control ECUs between years. Benson X simply put a switch in between the two wires and it worked for his according to that other link. Hey, if it's working then run with it

 

Yeah I noticed that, which was interesting. When I had it all apart and was troubleshooting earlier, I measured 9v coming off of the IG1 plug side and IIRC it needs to be <1v in order to trigger. I used to have a simple ON-ON switch in the past but I thought this was a more trick solution to have it come on with a locker and not have another switch to deal with.

This all originated because I wanted the locker light illuminated on the dash for a more obvious visual cue that I had a locker engaged.

 

Definitely a nice slick way to keep it OEM looking. Perhaps some floating voltage from the skid ECU was preventing it. It's basically works same way with the offroad models, they ground the harness side when engaged so that makes sense.

 

Thanks!

 

How did you get the ARB switches to fit in those slots? Dremel the switch or the slots? I have my compressor switch sticking out right now deciding whether to keep it or swap in a ch4x4. Thanks!

 

Sheeesh, this is legit! Cherry Bomb from the gram FYI

 

I dremeled the slots. If I dremeled a little much and the switch was loose, I would wrap some electrical tape around the switch to snug it up. Works really well.

 

Thanks -- -- I FINALLY got around to the dremel. Those switch panels have little flanges? on the inside. I removed those with the dremel and the ARB fit right in. I like the rocker/flip for these better than the push switch simply b/c I think I'll be much more aware of it and don't want it inadvertently on. And it's finally not sticking out 3/4" lol ... I cannot WAIT to get the lockers in place!