4wd actuator not actuating

You could, key on, fuse installed, black lead to a known good Ground and check both sides of the fuse one at a time with the red lead. Should be power on both sides if the fuse is good.

 

I’m getting constant power at the 4wd fuse. The fuse is before power is sent to the computer I assume? In which case the disconnect is between the fuse and ecu or at the ecu. Correct me if this is the wrong line of thinking

 

If you have power at the fuse but no power at the ECU, its the wiring in between the two

 

Ok sweet, glad this is getting narrowed down a bit, although following that wiring behind the dash seems a bit intimidating.

 

There is a junction box in between that the circuit goes through, I don't have time right now to look it up but it would be a good place to split the circuit.
If @TnShooter is around he might be able to find it.

 

I’m assuming this is the junction box in question but where is it located?

 

No this is the junction box in question (circled in Red), you can see that power from the 4wd Fuse comes in on Connector 3H Pin 22, goes out on 3H Pin 20, makes a loop, goes back in on Connector 3A Pin 9, and then goes out on 3A Pin 7 to the 4wd ECU.
If this was a 2nd gen I could tell you exactly which one and where it is but I'm not too familiar with 1st gens

 

Thank you so much! This looks like something I can wrap my head around. I’ll report back later

 

It's the J/B #3 junction box in the below pic.
It contains the 3A, 3D, and 3H connectors.

 

Yall are my saviors I finally think I’m getting close to resolving this. Thank you!

 

Before I dig in does anyone know if I have to pull the gauge cluster and all that to get to this?

 

That, I don not know.
Best I can do is try to google some pictures in hopes of finding it.
I got nothing better to do. So let me see if I can find a picture of the dash removed.....

 

I can get to this which I assume is 3A-3F but 3G-3I seem to be located somewhere else which makes this confusing

 

I found it. It's behind the A/C control switches.
Probably no fun to get to.

 

Sweet I traced everything back and gave all the connections a little wiggle. I’m now getting power at the ecu but still no blinking light

 

Let me catch up on this thread.
I only joined in today when Dm93 tagged me to help with the location of the junction box.

Let me read over the thread and see where to go from here.
In the mean time, Dm93 might jump back in at some point.
It will take me a bit to catch up and learn the system. I sold my 1st long before I ever had any issue with it.
So I'm not too familiar with the workings.

 

Let's go back to this post and answer the second half of the question.
Let's see if the 4WD selector button is working.

https://www.tacomaworld.com/threads/4wd-actuator-not-actuating.859713/page-2#post-30685165


"Pin 4 (Red) is the selector switch input, it should be grounded when the switch is depressed."

 

When switch is not pressed I get 12.24v and when it is pressed I’m getting 0.04v which seems backwards but I’m not sure.
Also, I’m testing all of the outputs to ADD, transfer case, etc and not getting any voltage.

 

Is that with the plug, plugged into the 4WD ECU when tested?
If so, that is normal.

The 4WD system on these trucks is a pull down system.
The 4WD ECU puts out 12v. When the switch is pressed, the path to ground is completed. Pulling down the 12v from the ECU.

Only thing we need to know right now is if the plug was plugged in when you tested the switch? or unplugged?

 

Plugged in to ECU when tested. None of the outputs change voltage though. Constantly at 0 volts