Ok this may sound a little confusing but it does perform a very functional task. In it basic form it will it take any electric controlled single wire selectable locking diff and automatically unlock it while you are in reverse. When you move the shifter out of reverse it will lock back in. I came up with the idea because when I was backing my truck down an obstacle (yes I have failed attempts to) it would be hard to steer or end up breaking berfields. Not to mention how many times I would forget to lock it back in. So that was the need that created this system. I even put in an addition switch as an override to the system (just incase I need the front diff locked in reverse.). It works quit simple with a relay in the circuit for the control wire for the air solenoid (if it is an ARB) with the signal from the backup lights controlling the relay. And the extra switch wired to bypass the relay. If you have a factory Toyota e-locker this can still be done it will just be more complicated (if you have a Toyota e-locker contact me and I will show you how to set it up)... The wiring diagram below is for a typical ARB install. The items below are what are additionally required after the lockers initial installation:
1x 5 terminal 12v relay (Sorry about not having a PN. Just used to scrounging)
I'm liking this idea. I've never used a relay in this fashion before in that I'm assuming the connection between 87a and 30 is (default) closed, and then when power is applied to activate the relay (85 terminal), it opens up that connection and disconnects the current flow? So basically using that 87a terminal, it makes the relay work the opposite of how we would normally wire it to run aux lights, fan, etc.