My 4 x 4 light is on when I’m in 2 wd. It goes out when I pull it down into 4 high.
how can I fix?
Truck had a ATS stage 1 68RFE trans when I purchased.

 

Sounds like something got wired wrong.....

Looking at the wiring diagrams, it appears that the t-case selector switch clues in the cluster that the truck is in 4 wheel drive. How that would become backwards is beyond me. Bad switch??