4X4 not working

I replaced the actuator and I still do not have the light in floor board to show it is in 4 wheel drive. I also replace the bulb. How can I test the wiring to eliminate transfer case switches, etc.

You can try unplugging the wires and use an ohm meter to test to see if the circuit opens and closes as some one shifts it in and out of 4wd. You should also check the wiring to make sure you don't have a broken wire. If you have the updated 3 wire actuator then your front diff is always engaged, until power is supplied to disengage. They did this as a fail safe in case you have an actuator fail when 4wd is needed.