Sprinter 3500 L5-2.7L DSL Turbo (2004)
Rain Sensor Control Module
The Rain Sensor Control Module (RSCM) is the primary component of the automatic wiper system. The RSCM is secured with two screws and nuts to a
bracket located under the instrument panel above the throttle pedal within the passenger compartment. The rectangular molded plastic housing of the
RSCM has an integral mounting tab on each side and an integral connector receptacle on one end, which contains the module terminal pins. These
terminal pins connect the RSCM to the vehicle electrical system through a dedicated take out and connector of the instrument panel wiring. Concealed
and protected within the RSCM housing is the electronic circuitry of the module.
The RSCM cannot be repaired and, if damaged or faulty, the entire module must be replaced.
The microprocessor-based Rain Sensor Control Module (RSCM) is only used in vehicles equipped with an optional automatic wiper system. The RSCM
monitors inputs from the ignition switch, the wiper and washer switch circuitry of the multi-function switch on the steering column, the park switch
within the wiper motor, and the rain sensor on the inside of the windshield glass. Based upon these inputs the RSCM sends the proper control outputs to
the wiper motor and the washer pump motor to provide all of the requested wiper and washer system functions.
The RSCM operates on battery current received from a fuse in the fuse block on a fused ignition switch output (run-start) circuit so that the RSCM will
operate whenever the ignition switch is in the On or Start positions. The RSCM receives ground at all times through its connection to the instrument
panel wire harness. It is important to note that the default condition for the wiper system is automatic wipers Off; therefore, if no input is received from
the rain sensor by the RSCM, the automatic wipers will be disabled and the RSCM will default the wiper and washer system to normal manual operation
for continuous low or high speed wiper or washer mode.
The hard wired RSCM circuits may be diagnosed using conventional diagnostic tools and methods. However, conventional diagnostic methods may not
prove conclusive in the diagnosis of the internal circuitry of the RSCM. Refer to the appropriate wiring information.
