Part time light stays on

When I swith in to any 4 wheel drive setting then back to 2 wheel drive the light that says part time stays onn for a while sometimes it goes off after a few feet sometimes miles. the jeep had been sitting for probably 3 years before I got it wasnt started anything. My question is what could be causing the light to stay on?

I believe the switch for the light is in the vacuum actuator motor which would mean its not the light, its the fact that you actually are still in 4wd. If it doesnt come out of 4wd within a few feet, try backing up 10-15 feet. Also take your vacuum actuator motor apart and make sure its not all gunked up in there and also that the shift fork is still intact.

Dean