Adding OEM Front Locker

[sdb999]

96' stock truck with no rear or front locker today. I'm swapping in a rebuilt front axle that happens to have the OEM locker. It's fully functional so I'd like to go ahead and wire up the front. I've sourced the OEM dash switch and Axle to Chassis harness and wondering if it's that simple....plug-n-play?

The switch seems to be configured to lock just the rear in first position, then moving to second position both front and rear. Any reason it wouldn't work with no rear lock?
Thanks, S.

 

[-Spike-]

You'll need the locker ECU, and you'll need to trick it into thinking the center and rear diffs are locked, which shouldn't be difficult at all. You could hook the center diff lock indicator switch to the pins for both center and rear, or just run 12v to those pins to be able to lock it at will. I'd go with the first option myself.

If you want to wire it without the ECU it gets tricky, but I'm pretty sure it's been done, the info is probably on the board somewhere.

 

[Pin_Head]

The stock OEM front locker won’t lock if the rear is not locked first. You would either have to fool the ECU that the rear is locked or wire it independently. You can get an independent locker wiring harness from the 12 volt guy.

 

[sdb999]

Thanks for quick response.

So as I see it:
The Diff Lock ECU is not on all trucks, only those optioned as such.
Front Diff Lock was only delivered with Rear and/or Center Locking Diffs, and of course with ECU.
ECU is the same for all vehicles with any combination of Diff Locks.
ECU (if used) must be "tricked" by supplying/jumping 12v to appropriate inputs for Rear and Center locked.
ECU can be "bypassed" by wiring directly to dash switch (OEM or Other)

Nothing too dramatic, except finding and ECU, assuming the chassis is harnessed for this device on all vehicles. I'd like to add Rear and Center down the road so don't want too much hacking into the harness if I can help it.

 

[Pin_Head]

All 80s have a locking center differential. All 80s 93 and later have the main wiring harness for F & R lockers, but are missing the terminal wiring harnesses, ECU and switch.

 

[White Stripe]

You can wire in a momentary switch with the engagement sensor wire to a light on the dash and engage it that way.

 

[landcrshr]

With the factory ECU you can just re-pin the connector so that the front diff signals are in place of the rear ones.

 

[MUDZLLA]

I think it would be easiest to wire up a new DPDT switch with an indicator light to show when it's locked. The indicator switch is independent of the actuator wiring so can be wired separately. The actuator wiring is a bit tricky and the FSM should be consulted. AFIK the acturator motor stops on it's own when it reaches the in or out limit. There's a common ground and out and in pins on either side. Power is independant and is supplied to two separate pins. The polarity of the power pins switches depending whether you are going in or out. Best to bench test the third member with your wiring setup before installing it. My 2 centavos...

 

[george_tlc]

or something that deals with the limit switches etc... But doesn't care about center diff or low/high range etc etc.

Slee - Electrical Switches

Specialist in Toyota 80 Series Land Cruisers. Hard to find parts, off-road accessories and custom fabrication

sleeoffroad.com

cheers,
george.

 

[landcrshr]

The factory diff-lock ECU has a time-out feature that makes it worth using IMO. If it doesn't see the actuator in position within 6 seconds, it removes power from the actuator motor, protecting it from burnout.

 

[ppc]

You'll need the locker ECU, and you'll need to trick it into thinking the center and rear diffs are locked, which shouldn't be difficult at all. You could hook the center diff lock indicator switch to the pins for both center and rear, or just run 12v to those pins to be able to lock it at will. I'd go with the first option myself.

If you want to wire it without the ECU it gets tricky, but I'm pretty sure it's been done, the info is probably on the board somewhere.

The stock OEM front locker won’t lock if the rear is not locked first. You would either have to fool the ECU that the rear is locked or wire it independently. You can get an independent locker wiring harness from the 12 volt guy.

Only the confirmation of the center diff being locked is required before the front locker can be activated. There is no confirmation required of the rear locker before the front will lock. Yes the mechanical function of the locker switch switches the rear locker first but will not impact the front locker if the rear is not present/connected. No switching of pins required in the dash switch.

The requirements to install the front locker only are five things:
1 the front locker
2 the front locker wiring harness ( harness connectors may need to be repinned if the harness if not a matching model year)
3 the locker dash switch
4 bulbs to install in the dash for the indicator lights
5 the front/rear locker ECU

 

[-Spike-]

Only the confirmation of the center diff being locked is required before the front locker can be activated. There is no confirmation required of the rear locker before the front will lock. Yes the mechanical function of the locker switch switches the rear locker first but will not impact the front locker if the rear is not present/connected. No switching of pins required in the dash switch.

That makes sense. I just have it stuck in my head that the rear needs to lock first, but only because that's how the switch works.

 

[sdb999]

@ppc greatly appreciate the short list. I have all the components except ECU. Search thus far has produced nothing. How rare are these to find?

 

[slow95z]

I have two spare locker ecus if you want to go the stock route and a spare switch.

 

[sdb999]

@slow95z PM'd you. Thanks, s.

 

[philucero]

All 80s have a locking center differential. All 80s 93 and later have the main wiring harness for F & R lockers, but are missing the terminal wiring harnesses, ECU and switch.

Howdy, I know this is an old thread but I have a 1996 non locker and I got 2 locking axles, front and rear, you mention the wiring is integrated but I'm wondering where it ends, I assume there is nothing underneath going to the axles? Where would I plug in the axle harnesses once I get them?
Would you just get the switch and harness from 12volyguy or lowrangeoffroad and forget about OEM ECU and switch?

 

[sdb999]

We were in a situation only adding front OEM locker with an axle rebuild. ECU, switch and front harness.....plug/play. We actually built the harness. In the front we found an empty connector waiting to plug our harness into. All out in the open, pretty straight forward. The rear, as I understand it, is more complicated. I believe you have to run from the Switch all the way back to the rear but I'd ask others to confirm.

 

[Pin_Head]

The wiring is there in the main harness, but you still need a few parts, like the switch, the relay box and the terminal wiring ends that go from the main harness to the F and R lockers.