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Discussion Starter #1
Hi guys, I've been posting on an old thread I was using for the hack and it's not getting much traffic. So I wanted to post a new thread in hope of getting some help. I performed this hack Rear diff lok on demand hack - Toyota FJ Cruiser Forum

It causes instant abs, vsc, and diff lock lights to come on as it should but the diff lock only blinks. I played around with it 's pattern, rocking etc but light won't stay on solid. I even put it in low lock to see if it would work as it did prehack... Nothing. If I performed the hack wrong would this be the result? Or as I suspect if I did the hack wrong I'd get constant check engine light, sparks and flames etc etc.

Any help ideas or speculation is most welcome.
 

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Discussion Starter #2
Been playing with it on my gravel drive. vsc and abs are disabled as indicated by dash lights,,, I can easily fishtail the rear end and lock the brakes. With the diff lock switch engaged both rear wheels break loose but with the switch off both rear wheels spin too 'don't know what to make of that'. I tested this on my wet lawn. I assume that even with diff unlocked the vsc is causing both rear wheels to spin??
 

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Did you cut the purple/red stripe wire? I didn't cut the speed wire. You'll have to driving less than 5mph for it to engage, rolling pace. The first time after my hack, my diff lock light would blink for over a minute. I wasn't sure I had it right and then eventually started engaging quickly after the RR lock switch is pushed. When was the last time you switched it on?

The rear wheels slipping over wet lawn isn't the whole truth. Both rear wheels may still get torque applied to them. I'm sure if you turned and were doing donuts, you'd notice the one wheel wonder.
 

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Discussion Starter #4
I did no doughnuts since I was in the yard.. I already have a bunch of burn outs out there, Haha. I did the speed wire cut. I used the locker around a month ago. I had to rock it a bit for it to actuate but it only took a few rocks and less than 5 mins. It did blink awhile though at first. After the hack it should blink then engage as normal right? Or does the hack cause the light to constantly blink even when locked?
 

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@cliffy The locker light will blink and go solid when engaged as normal. If it's still blinking, leads me to believe it's not locked yet. Hmmm, I'm pretty sure you would have got it right. I'm color blind and I was able to get it right :grin Double check the ground/ring terminal you used to ground. If the VSC/trac lights are active, that's a good sign. I would drive it some more with the diff lock on demand engaged. See if any luck, the diff lock will kick in.
 

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Discussion Starter #6
I don't think I'm color blind but... my wife does. She cut the wires for me. If my ground was insufficient then would vsc, abs and diff lock dash lights come on? I assumed since all the lights came on and the diff was trying to lock then the mod must be done correctly.
I think I may tinker with it some more to see if it comes around. I really don't like the idea of leaving the switch on at speed. I fear engaging the diff while moving. I don't want it to bind and break something.
 

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Discussion Starter #7 (Edited)
@jamesepoop The wire she cut when looking at the reassembled harness is the third wire from the right. The one that goes to red crimp fitting.
Not my pic but it shows the wire I had her cut. To me it looks like third wire over.
 

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I don't think I'm color blind but... my wife does. She cut the wires for me. If my ground was insufficient then would vsc, abs and diff lock dash lights come on? I assumed since all the lights came on and the diff was trying to lock then the mod must be done correctly.
I think I may tinker with it some more to see if it comes around. I really don't like the idea of leaving the switch on at speed. I fear engaging the diff while moving. I don't want it to bind and break something.
I think your ground is fine. Then connect the purple/red stripe wire you cut (assuming it's the right one to begin with). That'll cause it to not engage above 5mph. Then you can drive around with the RR switch engaged. Basically it'll engage while stopped, near stop, or taking off. It's fine and you're not going to break anything. If you notice it finally locked, you can pull off the road and disengage the locker.

Edit: that wire looks correct to me in the picture. I'm just not sure about your wire for the speed cut. I'd re-connect that one and see how it goes.
 

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Discussion Starter #9
I think your ground is fine. Then connect the purple/red stripe wire you cut (assuming it's the right one to begin with). That'll cause it to not engage above 5mph. Then you can drive around with the RR switch engaged. Basically it'll engage while stopped, near stop, or taking off. It's fine and you're not going to break anything. If you notice it finally locked, you can pull off the road and disengage the locker.

Edit: that wire looks correct to me in the picture. I'm just not sure about your wire for the speed cut. I'd re-connect that one and see how it goes.
Update: I got tired of pissing with it and reading any thread I can find remotely related to diff locker. I took the baby to dairy queen, while going through the drive through on pavement I engaged it and slowly while turning I could hear a lot of tire scrub. I unlocked it heard the 'snapping branch' and heard no tire scrub. I'm 99% sure it's working! Now, why is the indicator light only flashing and not solid??

Yes, I know the danger of locking the diff on dry pavement but I'd rather spend a couple grand on a new rear end then go through life not knowing if a mod worked...:|
 

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Discussion Starter #10
If anybody has any ideas why the diff lock indicator light flashes even though the diff is locked please let me know. I guess it's not a problem since it's engaging but I like things to work as they should.
 

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Yes, I know the danger of locking the diff on dry pavement but I'd rather spend a couple grand on a new rear end then go through life not knowing if a mod worked...:|
You're fine there buddy. It's not going to catastrophically implode as the owner's manual implies.

I'm not sure why it flashes. Maybe it's time to slide under and remove the actuator and harness for a closer inspection?
 

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Discussion Starter #12
You're fine there buddy. It's not going to catastrophically implode as the owner's manual implies.

I'm not sure why it flashes. Maybe it's time to slide under and remove the actuator and harness for a closer inspection?
Ok, I slept on it.. What if I had my wife cut the wrong wire for speed sensor, instead by some miracle she cut a wire that 'tells' the computer diff is locked? If there is such a wire? Module may just rely on sensor input to tell when locked?
 

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Discussion Starter #14
@cliffy Try connecting the assumed speed sensor wire. And report back. Your homework for this morning :grin
I was thinking the same thing, but this easy mod kicked my ass so I've been putting off stuffing myself under the dash. I need to reattach that wire though and see what happens. I know the diff is engaging, the sound of the snapping branch it makes when locking seems to be almost instant now. I can hear and feel the tire scrub in 2wd so it should still be locked in 4wd although there is all kind of scrub and gravel noise in 4wd.
 

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I always used to check locker/LSD function with the vehicle jacked up... open diff - the wheels rotate in opposite directions when you turn one wheel by hand, locked they rotate the same way... no risk of breaking anything. Or you can do it with one jacked and then see if you can drive off the jack.
 

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Discussion Starter #16 (Edited)
Ok, Got the nannies off mod done.
New piece to the puzzle.. Seems to be working except with all dash lights off when I lock the diff I get diff lock 'still flashing' and the sound of diff lock engaging but abs, vsc lights stay off now, when they used to illuminate with diff lock.... wtf does that mean? Are the two mods conflicting or is this normal?

I also want to mention @FatJohnson because I know he has my same set up.
 

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Discussion Starter #17
Ok, I reconnected what I thought was speed sensor wire and no change. The rear diff lock is engaging but indicator light on dash only blinks never stays on 'solid'.
I do believe it to be the speed sensor wire because I have no other obvious symptoms of that wire being cut.
After the nannies instant off mod performed I'm now not getting the vsc and abs lights when diff is locked.... is this normal?
Question for guys with instant off nannies mod. What lights come on your dash when engaged and when you engage diff lock what lights are you getting?
 

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Discussion Starter #18 (Edited)
Allright, End result..
Turn off my nannies off switch all lights off, as should be........GREAT!

Turn on switch abs and swerving FJ symbol and vsc off.... maybe great?

Question is I see another indicator light that says vsc trac, isn't that traction control and don't I want that disabled with the others?

Here are two pics one with key on before start to show vsc trac light and a pic FJ started with my nannies off switch on/open.

Rear diff indicator light still only blinks but diff is locking/unlocking.

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Turn on switch abs and swerving FJ symbol and vsc off.... maybe great?

Question is I see another indicator light that says vsc trac, isn't that traction control and don't I want that disabled with the others?

Here are two pics one with key on before start to show vsc trac light and a pic FJ started with my nannies off switch on/open.
Your lights look like mine when I activate rear diff hack (with the exception of the rear locker light)

I believe the VSC Trac light operates when it's actively working/car is sliding in normal operating conditions. I'm not looking down at my gauges when I'm slipping in a normal situation, but from the corner of my eye, I assume the swerving skid FJ and VSC Trac lights are both illuminating and flash when in a loss of traction situation. So the light that VSC Off is illuminated is fine when the diff lock is engaged. Go out and hit some back roads and test her out.
 

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Discussion Starter #20 (Edited)
Your lights look like mine when I activate rear diff hack (with the exception of the rear locker light)

I believe the VSC Trac light operates when it's actively working/car is sliding in normal operating conditions. I'm not looking down at my gauges when I'm slipping in a normal situation, but from the corner of my eye, I assume the swerving skid FJ and VSC Trac lights are both illuminating and flash when in a loss of traction situation. So the light that VSC Off is illuminated is fine when the diff lock is engaged. Go out and hit some back roads and test her out.
Ok, So the mod is correct and the vsc off doesn't illuminate with nannies off hack?
I 'tested' it last night. I can get pretty squirrely and lay a nice black layer of my over priced Nittos on the blacktop. (don't judge me! was purely for testing purposes only)

The funny thing is when nannies are on and I get heavy into boost 's/c' it'll throw a swerving FJ light. With nannies off I boost it and of course the light is already illuminated but after I slow turn nannies back on with my switch and nothing changes... all lights remain illuminated. It seems once I hit the point under boost where nannies would normally kick in then the switch won't turn them back on. I must then cycle the ignition key to 'reset' my switch then on/off operation works again. If that makes any sense.
@amaclach says his dash looks same as ours so I guess mod was a success. The only difference now would be my diff lock indicator only flashes. I know it engages in 2wd I can hear it lock/unlock and see/feel tire scrub. I guess in 4wd hi/lo it could not be engaged? I can still feel tire scrub in gravel but I assume this would be the case with 4wd engaged?


Thanks friends for your help! I know it's a lot of reading... I don't usually run into this much difficulty modding. I research mods pretty well before attempting them so I know what I 'm doing. I think this was a combo of claustrophobic working conditions and small color coded wires..
 
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