Grand Cherokee 2WD Limited V8-4.7L (2002)
Wiper Arm: Description and Operation
Rear Wiper Arm
Fig.7 Rear Wiper Arm
REAR WIPER ARM
The rear wiper arm is the rigid member located between the rear wiper motor output shaft that protrudes from the outer liftgate panel near the base of
the liftgate glass opening and the rear wiper blade. This wiper arm features an over-center hinge that allows easy access to the liftgate and lift-gate
glass for cleaning. The wiper arm has a die cast metal pivot end. This pivot end has a hole in it with internal serrations and a plastic pivot cover is
secured loosely to and pivots on the wiper arm hinge pin to conceal the wiper arm retaining nut. The wide end of a tapered, stamped steel channel is
secured with a hinge pin to the pivot end of the wiper arm. One end of a long, rigid, stamped steel strap, with a small hole near its pivot end, is riveted
and crimped within the narrow end of the stamped steel channel. The tip of the wiper blade end of this strap is bent back under itself to form a small
hook. Concealed within the stamped steel channel, one end of a long spring is engaged with a wire hook on the underside of the die cast pivot end,
while the other end of the spring is hooked through the small hole in the steel strap. A molded plastic wiper arm support is snapped onto the wiper arm
strap where it exits the channel. The entire wiper arm has a satin black finish applied to all of its visible surfaces.
A wiper arm cannot be adjusted or repaired. If damaged or faulty the entire wiper arm unit must be replaced.
The rear wiper arm is designed to mechanically transmit the motion from the rear wiper motor output shaft to the rear wiper blade. The wiper arm
must be properly indexed to the motor output shaft in order to maintain the proper wiper blade travel on the glass. The wiper arm support is designed
to lift and support the rear wiper arm and blade off of the glass when the rear wiper blade is parked. This support and the park ramp on the liftgate
outer panel below the glass also provide an alignment reference to ensure accurate rear wiper arm and blade installation. The hole with internal
serrations in the wiper arm pivot end interlocks with the serrations on the outer circumference of the motor output shaft, allowing positive engagement
and finite adjustment of this connection. A hex nut secures the wiper arm pivot end to the threads on the motor output shaft and the pivot cover hinges
and snaps over this connection for a neat appearance. The spring-loaded wiper arm hinge controls the down-force applied through the tip of the wiper
arm to the wiper blade on the glass. The hook formation on the tip of the wiper arm provides a cradle for securing and latching the wiper blade pivot
block to the wiper arm.
