Yet another 4wd not working....but rear locker works??

You have a MT
Doesn't have the neutral position switch for AT

 

If your rear differential lock is engaged when Tcase is in 4Lo the switch on passenger side of Tcase is working.

 

Ok, so this may or may not even be relevant to the issue but I want to be sure we're talking about the same thing.

You mentioned that "When shifted to 4wd the 4wd position switch 84222-35090 located on top of Tcase DRIVERS side sends signal to Transmission Control Relay Module 89531-35050 located under passenger kick plate. "

HOWEVER.

the plug that was broken on drivers side and that I hardwired was not part number 84222-35090. I know this because I bought that part and the plug ends are not the same. My only assumption is that it is part number: 84222-35110 ( I am saying this because it has a blue connector plug not the grey found on part number 8422-35090)

The switch on the passenger side part number seems to be the same, because it also has a blue plug end, not the grey found on 84222-35090.

So, at this point I am unsure if my problem still lies in the driver side switch. My only guess is yes, but how I am not sure. The wires from the engine harness are soldered directly into the driver side switch. So maybe the head of the switch itself is bad (the part that is threading into the T-case). I do not know, but these switches are extremely basic, and failure on these switches seems like it can't really happen other than the electrical side.

Not sure what to do at this point, I guess the only thing left before taking it somewhere is to buy an ADD and see if that fixes it. Would a bad ADD still blink 4wd light or not light up at all?

Any other thoughts???

 

This made me go out to test the rear locker. Now the rear locker does not work. It was definitely working before I hardwired the driver side plug. So, this makes me think something is connected between those two things happening.

Ah the joys of working on your rig……

 

https://www.tacomaworld.com/threads...g-but-rear-locker-works.734546/#post-26156927

 

Yes ADD is up next. But now what to think of this rear locker business. Is the wiring on driver side switch somehow connected and was damaged when I soldered it? It was for sure working before, now it won’t engage.

 

I am guessing this is why the rear locker doesn't work anymore. My guesss is that because it is now hardwired, the switch doesnt sense when the signal is not switching from 4-hi to 4-lo and thus not letting the rear locker engage.

I am going to have to cut the splice again, re-attach the plugs, and try to replace the switch in it's entirety this time. Just so I can be back at square 1 where I started.... and probably go ahead and replace ADD as well.

 

Did your light ever flash or would it not light up at all until you fixed the ADD?

 

I hope you realize that there is a wiring harness connector that plugs into the blue connection shown in picture

 

i thought that was obvious... That was the start of this whole diagnosis. That plug had a broken end and wasn't connecting with the wiring harness properly. I chopped the two ends both wiring harness end and switch end to try to see if that was the issue but no fix.

You mentioned previously in the thread that the wiring harness connector plug could be chopped along with this plug and wired together, that the plugs were there just for serviceability. I did that and now the rear locker is not working.

So now I need to re-attach the two plug ends, both on the wiring harness side as well as the new switch plug so I can make that connection again and not have it hard-wired. Currently, I have no plugs in this connection. Engine harness is wired directly into switch pigtail. Is that clear ? I feel like there's a lot of miscommunications as it's harder to describe these things with words sometimes.

Then once that's back in order I need to move onto the ADD...

 

Removing the plug won't cause a problem, connecting the wrong wires together, or shorting will though.

 

I may have switched the wires. Oh no

There are two black wires coming off the switch side pigtail. Both black, no difference, but one likely sends signal through and one sends signal back.

On the engine harness plug side (the side that was not broken) there is a white wire, and a white with black stripe wire.

I'm going to reverse them and use the chopped off plug to see which wire goes where. I hope I did not cause more damage doing this and shorted it. I had a feeling I shouldn't have hard wired these...I am always for keeping things OEM but I just wanted to figure out what was going on.

 

So the rear locker definitely does not work now. I've made it worse officially.

Does anyone know how to remove the front ADD actuator on these? Is it possible without a tremendous amount of work?

 

https://www.tacomaworld.com/threads/replacing-add-actuator.449429/#post-13225688

 

Good video on repairing the actuator
https://youtu.be/3TqnZqi4Iw4

 

Alright, update time people!

I popped the ADD off this morning and cracked it open.

The worm gear on the motor had some rust, so I opened the motor side up and found that the brushes were not conacting the motor to engage it. I'm not sure what it was but the brushes had a lot of resistance in their slots. I sanded the brushes down to get them to not have as much resistance and popped the springs back in and they were not seized, allowing the spring to get them to contact the motor. Then I cleaned the whole thing like shown in the video above, popped it back in, and what do you know 4wd works! But...there's more...

the story doesn't end there. Because I started this thread stating explicitly that my rear locker works. Well now it does not.

The only thing that has changed was hard-wiring the driver side 4wd position switch.

I am thinking what may have gone wrong was when I was doing the splicing of the 4wd position wires.

There are two wires coming from the engine harness. One white, and one white with a black tracer. On the switch, both wires are black however.

What I may have done was wire the two wires from the engine harness to the wrong side of the switch wires, and maybe that is why it's not sending the signal to the rear locker anymore. I am going to go ahead and order a whole switch, part number 84222-35110 and try AGAIN to get an 02 sensor socket on it maybe to pull it off, splice back on the factory engine harness plug, that way if the wires have a certain polarity, it only fits one way. In the meantime I can maybe cut my splice and try the reverse, but just wanted to post here before potentially making things worse again.

At least 4wd works!!

Thanks for the help so far guys, hopefully I can get this thing sorted 100%.

 

Good work
Good video here for Rear differential Lock actuator.
https://youtu.be/aqPmA0J0Zco

 

I'm not gonna dive into that rear actuator just yet because I know it works perfectly. It worked up to the day I started messing with wires... Gonna reverse the wires and report back. If anyones got anymore thoughts , I know I've got a bit of a different scenario but I do want to ask one question pertaining to how the rear locker works.

IF the rear locker computer looks for the 4WD selector position switch and the J shift case is in 4WD low and you're moving less than 5mph the locker sees all it needs to engage.

But before all of this, the plug on the driver side - which is the 4WD POSITION SWITCH, was not plugged in clearly because of the broken plug. But the locker still worked.

Now there is a connection (a hardwired one in lieu of the broken plug) , and the locker stops working.

So does that 4wd position switch send signal to the rear locker and now since there is basically a potential short in that connection it's seeing its not letting it engage possibly? Even though there was no connection at all previously and rear locker engaged fine?

I mean, that's gotta be it right??!

 

The previous owner may have jumped pins and removed modules and relays to allow rear diff lock on demand regardless of Tcase position.
Removing the ABS is required to allow this. Is the ABS module and relay still present and plugged in?
Do you have an ABS light lit up with key in on position?
Also are we talking about a locker added later because 04 4x4s with locker are rare and I believe only available as an option on 6cyls.
Join Toyota owners.com by adding your VIN# you can get more information on build.

 

Yes its a factory TRD off road 2004. Factory e-locker. It's actually seems like a rare truck because it also has a J-shift and manual 6cyl.

ABS is lit up and seems to work. I do remember that when the rear locker was working and would engage, the ABS Light would light up along with it. Is that normal? Doesn't do that on my 3rd gen 4runner with e-locker.

So i do not think the diff lock was tampered with any way, just given the trucks history.