How do I engage the 4-wheel drive on a 1991 Chevy 2500 pickup that will not engage?

Answer 1

Need to check the 4x4 fuse in the fuse box with a test light first.

Then lay down under the front of the truck and look at the front Differential

housing, left side of the middle. You will see wires going to the 4x4 Actuator.

Take test light and check those connectors, one of them should be hot when

shifter is in 4x4 with key on. If not hot then check the wireing going to it, for a

broken wire. If wire does have power going to it ,Then replace the 4x4 Actuator.

IT SCREEWS OUT OF HOUSING.