Four wheel drive not working

Have not used the 4wd in 4-5 years. Switch on dash hasnt had lights, and the service 4wd has been on on the dash has been on for a year. Transmission went out and found holes in the transfer case, so replaced the transmission and the transfer case and the transfer actuator. Truck was hung in 4 low. Replaced the dash switch, all 3 sensors in the transmission, transfer case control module, front differential actuator, checked all fuses, removed, sanded and replaced ground wires under driver door. Still no power to dash switch and still getting the service 4wd on the dash. Took the transfer case actuator off and put the truck in 2wd. Rolled the rearend and reinstalled the actuator. Took the truck to 2 different 4wd shops and no one can figure out my problem. The dash switch lights up when the truck cranks and then no lights. Any thoughts?