Dodge Sprinter. Manual - part 91
WIPER RELAY
DESCRIPTION
A wiper relay is standard equipment on all models.
The wiper relay (or intermittent wipe relay) is
located in a dedicated receptacle on the bottom left of
the fuse block on the underside of the steering col-
umn (Fig. 33). The wiper relay is a conventional
International Standards Organization (ISO) micro
relay. Relays conforming to the ISO specifications
have common physical dimensions, current capaci-
ties, terminal patterns, and terminal functions. The
relay is contained within a small, rectangular,
molded plastic housing. The relay is connected to all
of the required inputs and outputs through the
instrument panel wire harness connector by five
male spade-type terminals that extend from the bot-
tom of the relay base. The ISO designation for each
terminal is molded into the base adjacent to the ter-
minal. The ISO terminal designations are as follows:
• 30 (Common Feed) - This terminal is con-
nected to the movable contact point of the relay.
• 85 (Coil Ground) - This terminal is connected
to the ground feed side of the relay control coil.
• 86 (Coil Battery) - This terminal is connected
to the battery feed side of the relay control coil.
• 87 (Normally Open) - This terminal is con-
nected to the normally open fixed contact point of the
relay.
• 87A (Normally Closed) - This terminal is con-
nected to the normally closed fixed contact point of
the relay.
The wiper relay cannot be adjusted or repaired. If
the relay is damaged or faulty, it must be replaced.
OPERATION
The wiper relay (or intermittent wipe relay) is an
electromechanical switch that uses a low current
input from the intermittent wipe logic circuitry
within the fuse block underneath the steering column
to control a high current output to the low speed
brush of the wiper motor. The movable common feed
contact point is held against the fixed normally
closed contact point by spring pressure. When the
relay coil is energized, an electromagnetic field is
produced by the coil windings. This electromagnetic
field draws the movable relay contact point away
from the fixed normally closed contact point, and
holds it against the fixed normally open contact
point. When the relay coil is de-energized, spring
pressure returns the movable contact point back
against the fixed normally closed contact point. A
resistor or diode is connected in parallel with the
relay coil in the relay, and helps to dissipate voltage
spikes and electromagnetic interference that can be
generated as the electromagnetic field of the relay
coil collapses.
The wiper relay terminals are connected to the
vehicle electrical system through a connector recepta-
cle in the fuse block. The inputs and outputs of the
wiper relay include:
• The common feed terminal (30) provides an out-
put to the wiper motor low speed brush through the
wiper control circuitry of the multi-function switch on
the steering column. When the wiper relay is de-en-
ergized, the common feed terminal is connected to
the input of the relay normally closed terminal (87).
When the wiper relay is energized, the common feed
terminal is connected to the input of the relay nor-
mally open terminal (87A).
• The coil ground terminal (85) is connected to
battery current through a fused ignition switch out-
put circuit whenever the ignition switch is in the On
position.
• The coil battery terminal (86) is connected to the
relay control output of the wiper, turn signals and
engine start control module within the fuse block
through the wiper relay control circuit. This elec-
tronic circuitry controls the ground path for this cir-
cuit internally to energize or de-energize the wiper
relay control coil based upon its programming and
inputs from the wiper and washer control circuitry of
the multi-function switch, the wiper motor park
switch, and the ignition switch.
• The normally open terminal (87) is connected to
the output of the wiper motor park switch through
the wiper motor park switch sense circuit. This cir-
cuit can carry either battery current (wipers are not
in park position) or ground (wipers are in park posi-
tion), depending upon the status of the wiper park
switch.
Fig. 33 Wiper Relay
1 - HOUSING
2 - TERMINAL (5)
3 - BASE
8R - 34
WIPERS/WASHERS
VA