A four-wheel-drive shift may not complete if the required vehicle speed, transmission position, or other operating conditions have not been met. Start by checking the procedure for the specific mode in your owner's manual.
If the procedure is correct, possible causes include a control or wiring fault, an actuator problem, an axle engagement concern, or an internal transfer case issue.
Certified Transmission at 2112 West Broadway in Council Bluffs can inspect the system. Tell us whether the indicator flashes, stays off, or displays a message, and avoid repeatedly forcing the shift.