I have a 2000 blazer that is stuck in 4 wheel and 2 wheel drive, the front wheels will not turn freely when in 2 wheel drive even tho the light is in 2 wheel drive
see if your actuator cable that engages the front axle is seized, or check to see if the front actuator is recieving vacuum. In 2wd it shouldnt, in 4x4 it will. When it recieves vacuum it pulls the cable. If the cable binds it may have had enough force to pull it into 4x4 but wont let it release.