95 Jimmy encoder motor problem

I have a 95 s15 Jimmy. When I push the 4hi or 4low I can hear the encoder motor working but the light just flashes and it won't go in to 4X4. Is it possible to take the encoder motor off and switch it to 4hi or 4low manually from 2 hi. It's just a plow truck that I use on my driveway, and the driveway is about 100ft, so I don't feel like shoveling all the snow that is coming in 2 days

if it wont go in , its probly the accuater on the front diff, if you have bin plowing snow you might have pulled the wires off the accuater