1996 truck. 4wd light comes

On the front axle is an electronic solenoid that plunges in or out to engage or disengage the front drive axle for 4x4 operation.There is also a corresponding switch on the transfer case.I would replace the switch and the front axle solenoid.Over the years,i have applied this repair to dozens of Chevy trucks with successful results.There is also a GM Technical Service Bulletin on the transfer case switch,as it has been known to accidentally command the front axle into 4x4 mode at interstate speeds and completely wipe out the front axle.Good luck.