2006 Tacoma Rear Diff Lock doesn’t activate, no light on dash.

Hello,
I have bought a 2006 Tacoma TRD Off-Road with the rear diff lock. However I cannot get the diff lock to engage nor does the light on the dash come on at all (No blinking light, no solid light). I am putting it into 4Lo (Which does engage) and pushing the button while in neutral.
I pulled the button out and looked at the rear axle to verify both are real, which they are.
Absolutely lost on how to even start finding the issue, everything online is just about the blinking light.
Any input is much appreciated.
Thanks.

 

Wonder if someone replaced the 4wd ECU with one from a non-TRD truck, can you get the part number off it?

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

If you don't use it, you lose it. Regular use keeps everything lubricated.

I made the mistake of not engaging the diff lock for several years while my wife was the primary driver of our Tacoma. After we bought her another car to drive, we kept the Tacoma as a 3rd vehicle. I started driving it a lot more. Mine didn't want to engage when I started driving it again. This was at the height of Covid. A lot of things were closed, couldn't go anywhere anyway, but turkey season was open. I hunted almost every day of the season to get out of the house and be away from other people.

That meant driving 10-20 miles on dirt roads most every day for 6 weeks. I started driving into and out of my hunting spot in 4 lo and just kept trying to engage the diff lock. After several days it started engaging. The 1st few days it didn't ever engage, then I might have to drive 1/2 mile or more after pressing the button, but the more I used it the better it worked. By the end of turkey season, it was working normally. I now make sure to engage the diff lock on a pretty regular basis and have had no more problems.

You don't have to engage the diff lock at a stop and in neutral. You need to be in 4 lo, in gear, and moving. When you push the button it's normal for it to take a few seconds and you may have to drive 10-20' before it engages. That's why you don't wait until you're stuck to engage it.

 

Good points but the light should still flash when the switch is depressed, tha fach that we have no light suggests that:

The switch input isn't getting to the 4wd ECU.
The 4wd ECU is incorrect for the vehicle
There is an issue with the diff lock indicator/circuit
Or the 4wd ECU has failed


The easiest first step so we don't go down a rabbit hole is to verify the correct 4wd ECU is installed.

 

interesting you drive in 4low and let it engage while moving, good to know thats copasetic

i always found it funny how toyota and people on here say dont use it until you need it...seems smarter to notice a tough section of trail and engage it prior to burying vehicle or getting stuck, and being immobile trying to engage it.

OP, i suggest finding a sandy section or park in grass in order to help convince the locker to engage

 

I will take a look at this today and come back with some info, good starting place. The truck has slight damage so I can see that being a possibility

*edit* just realized you are first commentor lol

 

correct no light whatsoever, can still try but have had no luck with the hours I’ve spent trying before… will try first commenters idea and report back