Grand Cherokee 2WD V8-5.7L VIN 2 (2005)
(CAN) data bus. The FCM responds by activating or deactivating the front wiper system. The Steering Control Module (SCM) sends electronic
sensitivity level messages to the RSM over the CAN data bus based upon the driver-selected sensitivity setting of the control knob on the control stalk of
the right multi-function switch. The higher the selected sensitivity setting the more sensitive the rain sensor is to the accumulated moisture on the
windshield glass and the more frequently the sensor will send wipe commands to the FCM to operate the front wiper system.
Similarly the photocells within the RSM are able to sense ambient light levels through the windshield glass and provide electronic light level messages to
other modules in the vehicle over the CAN data bus. These messages can be used by the ElectroMechanical Instrument Cluster (EMIC)/Cab Control
Node (CCN) instead of the sun load sensor input to provide the automatic headlamps feature.
The RSM operates on battery current received through a fused B(+) fuse on a non- switched fused B(+) circuit. The RSM receives ground at all times
through a take out of the body wire harness with an eyelet terminal that is secured by a ground screw to the lower left inner C-pillar. It is important to
note that the default condition of the automatic wiper system is low. Therefore if no message is received by the FCM from the RSM for more than about
five seconds when in the Auto sensitivity wipe mode the wipers will default to a constant low speed continuous wipe mode.
The hard wired RSM circuits may be diagnosed using conventional diagnostic tools and methods. However~ proper testing of the RSM the FCM the
SCM and the electronic messages sent and received over the CAN data bus requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic
information.
