wont go into 4 wheel dr.light flashes on button
How often do you put it in 4WD?
I have been told if you don’t use it, it will get stuck. This happen to a Discovery Series One center diff lock.
The 4wd actuator is probably stuck, possibly from internal corrosion. If possible, whack it with a rubber mallet and see if the light goes out. If it does, you’ve found the problem.