Hilux Surf 4wd Issue

Hoping you can help guide me a little bit. Currently stationed in Japan and have a 1999 Hilux Surf so posting in hopes I can find some information! The issue is finding information specific for the Hilux Surf is a little more difficult over here and there is a language barrier when talking to mechanics.
Here is what is happening: I have a 1999 Hilux Surf 4 cyl that is having issues with the 4wd not disengaging and the 4 green and orange lights just flash. The front driveshaft is engaged and the wheels are locked like it is in 4wd but I cannot get it out. The handle in 2wd I push the 4wd M/M button and no change when I push it again to disengage the lights go out for a second then start flashing again. Moving to 4H or 4L and back to 2wd makes no difference. I have noticed no matter where I move the lever I never hear the click like 4wd is fully engaged but not sure if I should be considered something might be bad.
It is not a vacuum system so a lot of the information I found eliminates that part.
Actuator on the transfer case has been changed and did not change anything same problem, its still bad (mechanic suggested) and now suggests the front actuator. I checked the front actuator with battery power and it makes noise like it moves back and forth but the front drive shaft stays locked either way I move it.
I checked the 4wd switches (1 & 2) and they checked good for continuity, I looked at the 4wd control ECU and it looks fine. There are 2 switches on top of the transmission but I cannot get them out to check them.
Is a 4wd control ECU the next best part to try? Is there a source to find one because currently doesn't seem to be any out there.

 

Not familiar with the Hilux exactly...

Is it the ADD itself that isn't working (the actuator on the diff), maybe the sensor on the ADD itself, or the transfer case itself not going in 4x4?

There's also a switch on the driver side of the transfer case that can go bad and tell the ECU or not if it's engaged in 4x4 or not.

 

I'll be honest I feel dumb but I cannot find the sensor on the ADD actuator at all, I have looked all over and cant seem to locate it. The front driveshaft is engaged so I am assuming it is in 4wd.
I did just have something happen though when doing the checks to the transfer case actuator using a relay and battery power and the actuator moved. I put everything back together and when I was parked and engine off it worked! everything worked like normal 4wd engaged with ADD and with each selection on the control stick 4H and 4L. I drove around the block and only pushed the 4wd button for ADD and it went right back to the same issues so I definitely am not thinking the actuators are bad.
I will look for the transfer case sensor as well.