RAM 1500 Owner's Manual page 456

454 STARTING AND OPERATING
NOTE: Left to right wheel speed difference may be
necessary to allow the axle to fully lock. If the indicator
light is flashing after placing the switch in the REAR
LOCK or FRONT/REAR LOCK position, drive the vehicle
in a turn or on loose gravel to expedite the locking action.
WARNING!
Do not use the locked axle position for normal
driving. A locked front axle is intended for off-road
driving only. Locking the front axle during on-road
driving will reduce the steering ability. This could
cause a collision and you may be seriously injured.
To lock the front axle; move the axle locker switch to
FRONT/REAR LOCK while traveling less than 3 mph
(5 km/h). The indicator light will be solid when the front
axle is locked.
NOTE: The rear axle must be locked before the front axle
will lock.
To unlock the front axle; move the axle locker switch to
REAR LOCK. The FRONT/REAR LOCK indicator light
will go out when the axle is unlocked.
NOTE: The axle lockers could be torque locked due to
side to side loads on the axle. Driving slowly while turning
the steering wheel from a left hand turn to a right hand
turn or driving in REVERSE for a short distance may be
required to release the torque lock and unlock the axles.
To unlock the rear axle; move the axle locker switch to
AXLE UNLOCK. The REAR LOCK indicator light will go
out when the rear axle is unlocked.