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

The white wire with red stripe from 4Lo indicator switch traces to the ABS.
I'm not certain if diff lock turns ABS off which would cause an ABS light.
You have a rare Taco Gem
Last year of 1st gen
ECLB 6cyl 5MT 4x4 non button Jshift Elocker.Must be TRD SR5

 

You are mixing up the first two part numbers. I have a 2.7 4x4 manual transmission with j shift transfer case. 84222-35110 Is the only sensor/plug on my transfer case. I replaced actuator, and transmission control relay still no 4x4 - 84222-35110 fixed it. My assumption is that the ADD didn’t know the transfer case had moved and so didn’t lock the differential and didn’t light up the light. I had all the same problems described by OP.