Rear diff lock rebuild confusion

Joined
Apr 11, 2022
Messages
5
Location
Canada
Hey guys, ive been struggling to get my rear diff to work after rebuilding it, and im just unsure how the entire system works. The locker has been rebuilt and confirmed working. i hook up 9v and it spins all day long.

Ive re-timed it in the "locked" position and locked diff by hand to match so i can actually get the bolt back in for the guide, but no matter how i hook it up it refuses to move. My diff lock switch is also flashing no matter what i do to try and trick the sensor into thinking its locked, I dont know if that would help but im just generally lost, because even if i reinstall it as is itll just be stuck locked.

Ive heard from some folks that even when not installed correctly with the sensor it should just be able to "Lock" and "Unlock" while plugged in outside of the diff. But im clueless why its not working, just seems like the wiring doesnt want to send 12v even though i hear the ECU's relay click on.

Any input is appreciated, id love to just drive my cruiser again with a working diff lock since i cant really get the guide bolt back into its "Unlocked" position.
 
Joined
Feb 7, 2015
Messages
1,013
Location
Eastern Washington
Have you tested for 12v at the plug just before the locker? It's short duration (i.e. voltage is only present briefly) when it locks/unlocks so it helps to have someone turn the switch while you verify 12v. Attached is a test sequence in the FSM. Would at least rule out the wiring.
 

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Joined
Apr 11, 2022
Messages
5
Location
Canada
Have you tested for 12v at the plug just before the locker? It's short duration (i.e. voltage is only present briefly) when it locks/unlocks so it helps to have someone turn the switch while you verify 12v. Attached is a test sequence in the FSM. Would at least rule out the wiring.
Ill have to re-test, as im not 100% certain if i was doing it correctly, but i wasnt getting any voltage. For one split second it did move during further testing, and i could not replicate that any further. But im really hoping its just a fluke or something im not plugging in all the way. Will do more work on it tomorrow
 
Joined
Apr 11, 2022
Messages
5
Location
Canada
Im getting a whopping 0v everytime. But the odd thing is is it moved it once, it also seems like i reversed the polarity on the locker, i apply pos to 3 and neg to 2 and it unlocks instead of locks. So im not sure if that's causing issues when i plug it in. But im not sure how to give up and just re-install it not working, since i CANT reinstall it unlocked. Im lost but will continue on with testing.
 
Joined
Apr 11, 2019
Messages
572
Location
NJ
Just to cover troubleshooting questions
1. Are you putting truck in low 4 before engaging rear locker? Or using the center diff lock button?
2. If you short the rear diff lock switch, does the light turn solid? If not, then it’s possible your center diff lock switch is bad.

Try: short the center diff lock switch and engage rear locker. Does it move?

A bench test of the locker proves function with external power?

 
Joined
Apr 11, 2022
Messages
5
Location
Canada
It was the reverse polarity. Lol. The rebuild is simple as. I just made it more complicated than it needed to be, Cant wait to hit some of these nastier trails locked up!
 
Joined
Apr 11, 2022
Messages
5
Location
Canada
Glad you figured it out. Was going to ask if you redid the magnets or something to reverse the polarity.
By some miracle the front still works, so im back to having a true triple locked 80, i just pray my RTV job was good enough. so far no leaks, but we'll see with fresh Diff fluid. Glad the community can be so helpful! Looking forward to hanging around here.
 

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