Dodge 2001 Ram 1500, Owner'S Manual

Page: 726 / 2889

activates the washer pump/motor, which dispenses
washer fluid onto the windshield glass through the
washer nozzles.
When the ignition switch is in the Accessory or On
positions, battery current from a fuse in the Junction
Block (JB) is provided through a fused ignition
switch output (run-acc) circuit to the wiper motor
park switch, the wiper relay, and the multi-function
switch. The internal circuitry of the multi-function
switch provides a direct hard wired battery current
output to the low speed or high speed brushes of the
wiper motor when the Lo or Hi switch setting is
selected, which causes the wipers to cycle at the
selected speed. The intermittent wipe, and wipe-af-
ter-wash features of the wiper and washer system
are provided by the electronic intermittent wipe logic
circuit within the Central Timer Module (CTM). In
order to provide the intermittent wipe feature, the
CTM monitors the wiper switch state and the wiper
motor park switch state. In order to provide the
wipe-after-wash feature, the CTM monitors both the
washer switch state and the wiper motor park switch
state. When a Delay position is selected with the
multi-function switch control knob, the CTM logic cir-
cuit responds by calculating the correct delay inter-
val. The CTM then energizes the wiper relay by
pulling the relay control coil to ground. The ener-
gized wiper relay directs battery current through the
normally open contact of the relay back through the
internal circuitry of the multi-function switch to the
low speed brush of the wiper motor. The CTM moni-
tors the wiper motor operation through the wiper
park switch sense circuit, which allows the CTM to
determine the proper timing to begin the next wiper
blade sweep. The normal delay intervals are driver
adjustable from about one-half second to about eigh-
teen seconds.
The high-line and premium CTM also provides a
speed sensitive intermittent wipe feature. By moni-
toring vehicle speed messages received from the Pow-
ertrain Control Module (PCM) over the Chrysler
Collision Detection (CCD) data bus network, the
high-line or premium CTM is able to adjust the delay
intervals to compensate for vehicle speed. Above
about sixteen kilometers-per-hour (ten miles-per-
hour) the delay is driver adjustable from about one-
half second to about eighteen seconds. Below about
sixteen kilometers-per-hour (ten miles-per-hour) the
delay times are doubled by the CTM, from about one
second to about thirty-six seconds.
When the Off position of the multi-function switch
wiper control knob is selected, one of two events is
possible. The event that will occur depends upon the
position of the wiper blades on the windshield at the
moment that the Off position is selected. If the wiper
blades are in the down position on the windshield
when the Off position is selected, the park switch
that is integral to the wiper motor is closed to ground
and the wiper motor ceases to operate. If the wiper
blades are not in the down position on the windshield
at the moment the Off position is selected, the park
switch is closed to battery current through a fused
ignition switch output (run-acc) circuit. The park
switch sense circuit directs this battery current to
the low speed brush of the wiper motor through the
normally closed contact of the wiper relay and the
internal Off position circuitry of the multi-function
switch. This causes the wiper motor to continue run-
ning until the wiper blades are in the down position
on the windshield and the park switch is again
closed to ground.
When the Wash position of the multi-function
switch is selected, the Wash position circuitry within
the switch directs battery current to the washer
pump/motor. The CTM monitors the washer switch
state through a washer switch sense input. When the
washer switch is closed with the wiper system turned
Off, the CTM operates the wiper motor through the
wiper relay in the same manner as it does to provide
the Delay mode operation. After the state of the
washer switch changes to open, the CTM monitors
the wiper motor through the wiper park switch sense
circuit, which allows the CTM to monitor the number
of wiper blade sweeps.
Proper testing of the CTM, the PCM, or the CCD
data bus vehicle speed messages requires a DRBIII
t
scan tool. Refer to the appropriate diagnostic infor-
mation. Refer to the owner’s manual in the vehicle
glove box for more information on the features and
operation of the wiper and washer system.
DIAGNOSIS AND TESTING - WIPER &
WASHER SYSTEM
WIPER SYSTEM
The diagnosis found here addresses an electrically
inoperative wiper system. If the wiper motor oper-
ates, but the wipers do not move on the windshield,
replace the faulty wiper module. If the wipers oper-
ate, but chatter, lift, or do not clear the glass, clean
and
inspect the wiper system components as
required. (Refer to 8 - ELECTRICAL/WIPERS/
WASHERS - INSPECTION) and (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS - CLEANING). Refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
The following tests will help to diagnose the hard
wired components and circuits of the wiper system.
BR/BE
WIPERS/WASHERS 8R - 3
WIPERS/WASHERS (Continued)