This past winter I used my 4wd once on my 96 truck. I found it difficult to shift in to and out of 4wd. Especially to get it out of 4wd. So now it is not in 4wd but the 4wd indicator sometimes comes on solid then it flashes rapidly and then goes out. My truck was only used for snow clearing for it's entire existence before I bought it. Salt beat it up some. Is there some sensor that I can adjust or is this something possibly more serious?

 

the dash light is activate by a 2 wire switch on the driver end of the cad. when those wires are open, the light is off. when those wires are closed, the light will come on.

start simple. find, unplug, clean the connector. clean out all the mud, dirt, sand, salt, and crap. spray it out with wd40 or contact cleaner or carb cleaner, or MILD (not harsh) brake cleaner. with a helper, cross the pins to test the dash light.

next step is to check the vacuum lines at the cad. vacuum is required on one line to hold the shift collar in the 2wd position, and on the other to hold it in the 4wd position.
read all of this -
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm

if and only is your vacuum lines are correct, then the next step is to remove/test the switch.

the final step is to remove, test, fix the CAD and/or shift collar.