4x4 4HI light still flashing after brand new transfer case

I got a new transfer case installed on my 08 4.7 L because I couldn’t switch into 4x4. Yes we could’ve just changed out the actuator motor I think but the whole case looked horrible. After that getting replaced it still does not go into 4 wheel drive. What else could be the issue with the system?

 

The front differential must also be engaged for 4x4 action.

Maybe the issue was with the diff actuator.?

 

Could be a wiring issue too. I would do a little trouble shooting before I bought any more parts. It’s pretty easy to check continuity through the harness to make sure there are no broken wires. There is a pretty good trouble shooting section in the factory service manual.