2006 MERCEDES-BENZ SPRINTER ECO mode

right rear door is standard equipment on wagon mod-
els. The sliding and rear door jamb switches are not
available for van models.
²Entry/Exit Lamp- An entry/exit lamp to illu-
minate each front and sliding side door step well is
optional equipment on wagon models.
²Time Delay Relay- Vehicles equipped with the
optional remote cargo lamp switches also have a time
delay relay located in the electrical center within the
driver side front seat riser.
Hard wired circuitry connects the interior lighting
system components to the electrical system of the
vehicle. These hard wired circuits are integral to sev-
eral wire harnesses, which are routed throughout the
vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the interior lighting
system components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
OPERATION
The interior lighting systems can be divided into
two general classifications based upon the circuit
that controls their operation: The interior lighting
circuit, or the exterior lighting circuit. The hard
wired circuits and components of the interior lighting
systems may be diagnosed and tested using conven-
tional diagnostic tools and procedures.
INTERIOR LIGHTING CIRCUIT
Depending upon the vehicle model (van or wagon)
and the selected vehicle options the interior lighting
circuit may include dome/cargo lamps located over-
head in the front and rear of the vehicle, a dome/
reading lamp located in the header area above the
windshield between the sun visors, and entry/exit
lamps located in the front and sliding side door step
wells.
WAGON MODELS
In all wagon models, the lamps in the interior
lighting circuit are provided with battery current at
all times by a fuse in the fuse block beneath the
steering column. The front, side, and rear door jamb
switches control a ground path for each of these
lamps, except for the optional reading lamp. If the
lamp has an optional integral switch, that switch has
three separate positions. The first position provides a
ground path independent of the door jamb switches
to turn the lamp On. The second, or center position
allows the door jamb switches to control the lamp.The third position segregates that lamp from the
door jamb switch input, turning the lamp Off. In the
case of the optional dome/reading lamp, the integral
lamp switch has a fourth position which will illumi-
nate only the reading lamp bulb.
VAN MODELS
Unless a van model is equipped with an optional
remote cargo lamp switch, all of the lamps in the
interior lighting circuit operate the same way as the
wagon models except that there are only two door
jamb switches, one for each front door. If the vehicle
is equipped with an optional remote cargo lamp
switch, the lamps in the rear of the vehicle on the
interior lighting circuit are provided with battery
current by the time delay relay. The time delay relay
is a smart relay containing active electronic elements
that comprise an electronic timer logic circuit. When
the remote cargo lamp switches provide the proper
input to the time delay relay, the relay logic responds
by energizing the relay control coil. The energized
relay control coil provides battery current to all of
the lamps on the rear interior lighting circuit and to
the indicator Light-Emitting Diode (LED) units in
the remote cargo switches causing each to illuminate.
If a remote cargo lamp switch remains On for more
than about fifteen minutes, the time delay relay will
then automatically de-energize the rear interior
lighting circuits until the remote cargo lamp switch
is cycled Off and then back On.
EXTERIOR LIGHTING CIRCUIT
The exterior lighting circuit provides battery cur-
rent to the optional ash receiver/cigar lighter lamp
and to the illumination Light-Emitting Diode (LED)
unit within the remote cargo lamp switch in the
instrument panel accessory switch bezel whenever
the exterior lamps are turned On.
SPECIFICATIONS - INTERIOR LIGHTING
VALAMPS/LIGHTING - INTERIOR 8L - 29

BULB SPECIFICATIONS
LAMP BULB
Cargo/Dome Lamp K - 12V 18W
Dome/Reading Lamp K - 12V 10W
Dome Lamp w/Intrusion
SensorK - 12V 6W
Entry/Exit Lamp W5W - 12V 5W
ASH RECEIVER / CIGAR
LIGHTER LAMP UNIT
REMOVAL
An ash receiver/cigar lighter lamp unit is optional
equipment on this model (Fig. 1). The bulb and bulb
holder are secured by an integral mount to the out-
side of the cigar lighter halo ring, and serves to illu-
minate both the translucent halo ring and the ash
receiver. A small lens that is snap-fit into the inboard
side of the ash receiver bin allows light from the
lamp on the halo ring to also illuminate the ash
receiver. The ash receiver/cigar lighter lamp is ser-
viced only as a unit with the ash receiver housing
and cigar lighter receptacle. If the lamp is faulty or
damaged, the entire ash receiver housing and cigar
lighter receptacle unit must be replaced. (Refer to 23
- BODY/INSTRUMENT PANEL/ASH RECEIVER -
REMOVAL).
INSTALLATION
An ash receiver/cigar lighter lamp unit is optional
equipment on this model (Fig. 1). The bulb and bulb
holder are secured by an integral mount to the out-side of the cigar lighter halo ring, and serves to illu-
minate both the translucent halo ring and the ash
receiver. A small lens that is snap-fit into the inboard
side of the ash receiver bin allows light from the
lamp on the halo ring to also illuminate the ash
receiver. The ash receiver/cigar lighter lamp is ser-
viced only as a unit with the ash receiver housing
and cigar lighter receptacle. If the lamp is faulty or
damaged, the entire ash receiver housing and cigar
lighter receptacle unit must be replaced. (Refer to 23
- BODY/INSTRUMENT PANEL/ASH RECEIVER -
INSTALLATION).
CARGO / DOME LAMP BULB
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cargo/dome lamp unit from its
mounting location, but do not disconnect the vehicle
wire harness from the lamp connector receptacle.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
INTERIOR/CARGO/DOME LAMP UNIT -
REMOVAL).
(3) Grasp the lamp housing in one hand and care-
fully pull the bulb out of the bulb holder with the
other hand (Fig. 2).
INSTALLATION
(1) Grasp the cargo/dome lamp housing in one
hand and carefully insert the bulb into the bulb
holder with the other hand (Fig. 2).
(2) Reinstall the cargo/dome lamp unit into its
mounting location. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - INTERIOR/CARGO/DOME
LAMP UNIT - INSTALLATION).
(3) Reconnect the battery negative cable.
Fig. 1 Ash Receiver/Cigar Lighter Lamp Unit
1 - CIGAR LIGHTER
2 - HALO RING
3 - LENS
4 - LAMP UNIT (BIN REMOVED)
5 - ASH RECEIVER BIN
6 - ASH RECEIVER
Fig. 2 Cargo/Dome Lamp Bulb Remove/Install
1 - LAMP HOUSING
2 - BULB
3 - CONNECTOR RECEPTACLE
8L - 30 LAMPS/LIGHTING - INTERIORVA

travelling end-release seat belt buckles secured to
the inboard seat track. The driver side front seat belt
buckle of all models includes an integral seat belt
switch that detects whether its seat belt has been
fastened.
²Rear Seat Belts- All rear seating positions are
equipped with three-point seat belt systems. Each
rear seating position belt employs an integral seat
cushion frame mounted inertia latch-type retractor, a
fixed position upper seat back frame mounted turn-
ing loop, and a fixed lower seat belt anchor secured
to the seat cushion frame. All rear seat belts have
fixed end-release seat belt buckles that are also
secured to the seat cushion frame.
PASSIVE RESTRAINTS
A Next Generation driver airbag is standard facto-
ry-installed safety equipment on this model, while a
passenger side front airbag and side curtain airbags
are optional. This airbag system is a passive, inflat-
able, Supplemental Restraint System (SRS) and vehi-
cles with this equipment can be readily identified by
the ªSRS - AIRBAGº logo molded into the driver air-
bag trim cover in the center of the steering wheel
and, if the vehicle is so equipped, also into the pas-
senger airbag door on the instrument panel above
the glove box (Fig. 2). Vehicles with the airbag sys-
tem can also be identified by the airbag indicator,
which will illuminate in the instrument cluster for
about six seconds as a bulb test each time the igni-
tion switch is turned to the On position. A pyrotech-
nic-type seat belt tensioner is integral to the front
seat belt retractor mounted on the lower B-pillar on
the driver side, and to the passenger side retractor of
vehicles equipped with the optional passenger side
airbag.
The supplemental restraint system includes the
following major components, which are described in
further detail elsewhere in this service information:²Airbag Control Module- The Airbag Control
Module (ACM) is located on a mount on the floor
panel within the driver side seat riser, beneath the
driver seat in the passenger compartment.
²Airbag (SRS) Indicator- The airbag indicator
is integral to the ElectroMechanical Instrument Clus-
ter (EMIC), which is located on the instrument panel
in front of the driver.
²Clockspring- The clockspring is located near
the top of the steering column, directly beneath the
steering wheel.
²Driver Airbag- The driver airbag is located in
the center of the steering wheel, beneath the driver
airbag trim cover.
²Driver Knee Blocker- The structure of the
lower instrument panel serves as a knee blocker for
the driver.
²Passenger Airbag- The optional passenger air-
bag is located within the instrument panel, behind
the passenger airbag door on the instrument panel
above the glove box on the passenger side of the vehi-
cle.
²Passenger Knee Blocker- The structure of
the glove box door and the lower instrument panel
serve as a knee blocker for the front seat passenger.
²Seat Belt Tensioner- A seat belt tensioner is
integral to the driver side front seat belt retractor
unit, and to the passenger side front seat belt retrac-
tor unit on vehicles equipped with an optional pas-
senger airbag.
²Side Curtain Airbags- Optional side curtain
airbags are available for this model when it is also
equipped with dual front airbags. In vehicles
equipped with this option, a side curtain airbag is
located on the inside of the roof side rail within a
garnish molding that extends from the A-pillar to the
B-pillar above each front door opening within the
passenger compartment of the vehicle.
²Side Impact Sensor- Two side impact sensors
are used on vehicles equipped with the optional side
curtain airbags, one on each side of the vehicle. One
sensor is located near the front of each front door
step well, concealed behind the step well trim.
The ACM contains a central processing unit and
programming that allows it to communicate on a
serial data bus diagnostic circuit connected to the
16-way Data Link Connector (DLC) located below the
left end of the instrument panel. This method of com-
munication is used for initialization of the ACM and
for diagnosis of the SRS circuits and components
using a diagnostic scan tool.
Hard wired circuitry connects the supplemental
restraint system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system,
Fig. 2 SRS Logo
VARESTRAINTS 8O - 3

Communication Interface (SCI) data bus line for sup-
plemental restraint system programming or diagno-
sis and testing through the 16-way Data Link
Connector (DLC) located on the dash panel below the
driver side end of the instrument panel. A hard wired
output from the ACM is used for control of the airbag
indicator in the ElectroMechanical Instrument Clus-
ter (EMIC). (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER/AIRBAG INDICATOR -
OPERATION).
The ACM microprocessor continuously monitors all
of the supplemental restraint system electrical cir-
cuits to determine the system readiness. If the ACM
detects a monitored system fault, it sets an appropri-
ate Diagnostic Trouble Code (DTC) and sends an out-
put to the EMIC to turn on the airbag indicator. The
ACM illuminates the indicator for about four seconds
each time the ignition switch is turned to the On
position as a bulb test. If the indicator remains illu-
minated for about ten seconds after the ignition
switch is turned to the On position, the ACM has
detected a non-critical fault that poses no danger to
the vehicle occupants. If the airbag indicator illumi-
nates solid (not flashing) while driving or stays on
longer than ten seconds following the bulb test, the
ACM has detected a critical fault that may cause the
airbags not to deploy when required or to deploy
when not required. An active fault only remains for
the duration of the fault, or in some cases, for the
duration of the current ignition switch cycle, while a
stored fault causes a DTC to be stored in memory by
the ACM.
The ACM receives battery current through a fused
ignition switch output circuit. The ACM receives
ground through a ground circuit and take out of the
vehicle wire harness. This take out has an eyelet ter-
minal connector secured by a nut to a ground stud on
the floor panel directly below the ACM within the
driver side seat riser. A case ground is also provided
for the ACM through a ground circuit and eyelet ter-
minal connector secured under the left rear ACM
mounting screw. These connections allow the ACM to
be operational whenever the ignition switch is in the
On position.
The ACM also contains an energy-storage capaci-
tor. When the ignition switch is in the On position,
this capacitor is continually being charged with
enough electrical energy to deploy the supplemental
restraint components for up to one second following a
battery disconnect or failure. The purpose of the
capacitor is to provide backup supplemental restraint
system protection in case there is a loss of battery
current supply to the ACM during an impact.
Two sensors are contained within the ACM, an
electronic impact sensor and a safing sensor. These
electronic sensors are accelerometers that sense the
rate of vehicle deceleration, which provide verifica-
tion of the direction and severity of an impact. Onmodels equipped with optional side curtain airbags,
the ACM also monitors inputs from two remote side
impact sensors located within the left and right front
door step wells to control deployment of the side cur-
tain airbag units.
The safing sensor is an electronic accelerometer
sensor within the ACM that provides an additional
logic input to the ACM microprocessor. The safing
sensor is used to verify the need for a supplemental
restraint deployment by detecting impact energy of a
lesser magnitude than that of the primary electronic
impact sensors, and must exceed a safing threshold
in order for the airbags to deploy. Vehicles equipped
with optional side curtain airbags feature a second
safing sensor within the ACM to provide confirma-
tion to the ACM microprocessor of side impact forces.
This second safing sensor is a bi-directional unit that
detects impact forces from either side of the vehicle.
Pre-programmed decision algorithms in the ACM
microprocessor determine when the deceleration rate
as signaled by the impact sensors and the safing sen-
sors indicate an impact that is severe enough to
require supplemental restraint system protection.
When the programmed conditions are met, the ACM
sends the proper electrical signals to deploy the front
airbags and seat belt tensioners and, if the vehicle is
so equipped, either side curtain airbag unit.
The ACM also provides a hard wired electrical
crash signal output following a supplemental
restraint deployment event. This output is used to
signal other electronic modules in the vehicle to pro-
vide their enhanced accident response features,
which include automatically disabling the engine
from running and unlocking all of the doors. How-
ever, these responses are each dependent upon the
circuits, components, and modules controlling these
features remaining intact from collateral damage
incurred during the vehicle impact.
A single ACM is used for all variations of the sup-
plemental restraint system available in this vehicle.
This ACM is programmable and in order to function
properly it must be programmed for the correct vehi-
cle supplemental restraint system equipment using
an initialization procedure. The initialization proce-
dure requires the use of a diagnostic scan tool. Refer
to the appropriate diagnostic information. The hard
wired inputs and outputs for the ACM may be diag-
nosed and tested using conventional diagnostic tools
and procedures. However, conventional diagnostic
methods will not prove conclusive in the diagnosis of
the ACM or the supplemental restraint system. The
most reliable, efficient, and accurate means to diag-
nose the ACM or the supplemental restraint system
requires the use of a diagnostic scan tool. Refer to
the appropriate diagnostic information.
VARESTRAINTS 8O - 9

(3) If the vehicle is so equipped, snap the plastic
cover over the screw that secures the front seat belt
buckle lower anchor to the inboard side of the seat
frame.
(4) On the driver side only, reconnect the seat belt
switch pigtail wire to the vehicle wire harness and
push the joined connectors through the clearance
hole in the seat riser cover.
(5) On the driver side only, route and secure the
seat belt switch pigtail wire to the seat frame with
wire ties.
PASSENGER AIRBAG
DESCRIPTION
The rearward facing surface of the injection
molded, thermoplastic passenger airbag door is the
most visible part of the optional passenger airbag
(Fig. 27). The passenger airbag door is located above
the glove box opening in front of the front seat pas-
senger seating position on the instrument panel. The
upper and lower edges of the airbag door are secured
by a snap-fit to molded plastic clips. The two clips at
the top are each secured by a screw to the instru-
ment panel base trim, while the clips at the bottom
are integral to the panel that surrounds the passen-
ger airbag door opening in the instrument panel base
trim. The airbag door is also secured to the airbag
housing by two wide woven straps that serve as
hinges for the door upon an airbag deployment.
Located behind the passenger airbag door is the
passenger airbag unit (Fig. 28). The airbag housing
is constructed of a long U-shaped aluminum extru-
sion with two stamped steel end plates. A stepped
flange that extends from the back of the extrusion
serves as the airbag mounting flange. This mountingflange is secured with screws to a stamped steel air-
bag mounting bracket that is secured with screws to
the tubular steel instrument panel structural support
above the glove box opening. The end plates are
secured to each side of the passenger airbag housing
with screws.
The passenger airbag unit used in this model is a
Next Generation-type that complies with revised fed-
eral airbag standards to deploy with less force than
those used in some prior models. The airbag housing
contains the folded airbag cushion, the airbag
retainer, and the airbag inflator. The airbag is a rect-
angular fabric cushion. The airbag inflator is a solid
fuel, pyrotechnic-type unit that is secured to and
sealed within the airbag housing along with the
folded airbag cushion. The inflator initiator connector
receptacle is connected to the vehicle electrical sys-
tem through a dedicated take out of the vehicle wire
harness with a yellow connector insulator.
The passenger airbag and airbag door unit cannot
be repaired, and must be replaced if deployed, faulty
or in any way damaged.
OPERATION
The passenger airbag is deployed by an electrical
signal generated by the Airbag Control Module
(ACM) through the passenger airbag squib circuits to
the initiator in the airbag inflator. When the ACM
sends the proper electrical signal to the initiator the
electrical energy generates enough heat to initiate a
small pyrotechnic charge which, in turn, ignites
chemical pellets within the inflator. Once ignited,
these chemical pellets burn rapidly and produce a
large quantity of inert gas. The inflator is sealed to
the back of the airbag housing and a diffuser in the
Fig. 27 Passenger Airbag Door
1 - INSTRUMENT PANEL TRAY
2 - PASSENGER AIRBAG DOOR
3 - GLOVE BOX DOOR
Fig. 28 Passenger Airbag Unit
1 - DOOR
2 - CLIP (2)
3 - HOUSING
4 - CONNECTOR RECEPTACLE
5 - END PLATE (2)
8O - 24 RESTRAINTSVA

(8) Remove the seat belt turning loop height
adjuster from the inner B-pillar.
INSTALLATION
WARNING: To avoid personal injury or death, on
vehicles equipped with airbags, disable the supple-
mental restraint system before attempting any
steering wheel, steering column, airbag, seat belt
tensioner, or instrument panel component diagno-
sis or service. Disconnect and isolate the battery
negative (ground) cable, then wait two minutes for
the system capacitor to discharge before perform-
ing further diagnosis or service. This is the only
sure way to disable the supplemental restraint sys-
tem. Failure to take the proper precautions could
result in accidental airbag deployment.
WARNING: To avoid personal injury or death, during
and following any seat belt service, carefully
inspect all seat belts, buckles, mounting hardware,
retractors, and anchors for proper installation, oper-
ation, or damage. Replace any belt that is cut,
frayed, or torn. Straighten any belt that is twisted.
Tighten any loose fasteners. Replace any belt that
has a damaged or inoperative buckle or retractor.
Replace any belt that has a bent or damaged latch
plate or anchor plate. Never attempt to repair a seat
belt component. Always replace damaged or faulty
seat belt components with the correct, new and
unused replacement parts listed in the
DaimlerChrysler Mopar Parts Catalog.
(1) Position the seat belt turning loop height
adjuster onto the inner B-pillar (Fig. 42).
(2) Install and tighten the two screws that secure
the seat belt turning loop height adjuster to the
upper inner B-pillar. Tighten the screws to 35 N´m
(26 ft. lbs.).
(3) Position the front seat belt turning loop onto
the height adjuster on the upper B-pillar (Fig. 41).
(4) Install and tighten the nut that secures the
front seat belt turning loop to the height adjuster.
Tighten the nut to 35 N´m (26 ft. lbs.).
(5) Position the height adjuster trim to the upper
B-pillar so that the driver on the back of the trim
engages the lug of the height adjuster (Fig. 40).
(6) Reinstall the trim panel onto the inside of the
B-pillar. (Refer to 23 - BODY/INTERIOR/B-PILLAR
TRIM - INSTALLATION).
(7) Reconnect the battery negative cable.
SIDE CURTAIN AIRBAG
DESCRIPTION
Optional side curtain airbags are available for this
model when it is also equipped with dual front air-
bags. These airbags are passive, inflatable, Supple-
mental Restraint System (SRS) components (Fig. 43).
This system is designed to reduce injuries to the
vehicle occupants in the event of a side impact colli-
sion.
Vehicles equipped with side curtain airbags have
two individually controlled curtain airbag units.
These airbag units are concealed and mounted above
the front door openings where they are each secured
to one of the roof side rails. Each folded airbag cush-
ion is contained within a channel in the molded plas-
tic garnish molding that extends along the roof rail
from the A-pillar at the front of the vehicle to just
behind the B-pillar. A tether extends down the A-pil-
lar from the front of the airbag cushion, where it is
secured to the base of the pillar near the belt line
with a screw.
The hybrid-type inflator for each airbag is con-
nected to the airbag cushion by a tubular manifold.
The inflator bracket and the airbag cushion channel
are located with a stamped metal lug to a bore in the
roof rail, then secured with screws at the A-pillar in
the front and the B-pillar in the rear. A two-wire pig-
tail wire is routed from the airbag inflator down the
B-pillar where it connects the unit to a take out of
the vehicle body wire harness with a keyed and
latched connector insulator.
The side curtain airbag unit cannot be adjusted or
repaired and must be replaced if deployed, faulty, or
Fig. 43 Side Curtain Airbag
1 - GRAB HANDLE
2 - B-PILLAR TRIM
3 - SIDE CURTAIN AIRBAG
VARESTRAINTS 8O - 35

other minor debris from the outside windshield glass
surface that might be encountered while driving the
vehicle under numerous types of inclement operating
conditions.
Two wiper systems are available: the standard
intermittent wipe system, or an optional automatic
wipe system. The vehicle operator initiates all wiper
and washer system functions with the multi-function
switch wiper control stalk that extends from the
right side of the steering column, just below the
steering wheel. Depressing, raising, or pulling the
right control stalk of the multi-function switch
selects the desired wiper system operating mode (Fig.
2). The wiper system allows the vehicle operator to
select from two continuous wiper speeds, Hi or Lo,
either a fixed interval intermittent wipe mode or an
auto wipe mode (as the vehicle is equipped), and a
pulse wipe mode. Pushing the knob on the end of the
control stalk towards the steering column activates
the washer pump/motor, which dispenses washer
fluid onto the windshield glass through the washer
nozzles.
The hard wired inputs to and outputs from the
wiper and washer system components may be diag-
nosed and tested using conventional diagnostic tools
and methods. Refer to the appropriate diagnostic
information. Refer to the owner's manual in the vehi-
cle glove box for more information on the features
and operation of the wiper and washer system.
INTERMITTENT WIPE SYSTEM
When the ignition switch is in the On position, bat-
tery current from a fuse in the fuse block underneath
the steering column is provided through a fused igni-
tion switch output (run-start) circuit to the intermit-tent wipe logic circuitry of the wiper, turn signals
and engine start control module within the fuse
block, the multi-function switch, the wiper relay and
the wiper motor park 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 Low,
High, or Pulse position is selected, which causes the
wipers to cycle at the selected speed for as long as
that switch position remains selected.
In order to provide the intermittent wipe and wipe-
after-wash features, the intermittent wipe logic cir-
cuitry of the wiper, turn signals and engine start
control module within the fuse block monitors inputs
from the intermittent wipe and washer switch cir-
cuitry of the multi-function switch and the park
switch in the wiper motor. When the intermittent
wipe position is selected with the multi-function
switch control stalk, the intermittent wipe logic cir-
cuitry responds by energizing the wiper relay and
calculating the correct delay interval. The energized
wiper relay directs battery current through the inter-
mittent wipe position circuitry of the multi-function
switch to the low speed brush of the wiper motor.
The intermittent wipe logic circuit monitors the
wiper motor operation through the wiper on/off relay
output circuit, which allows it to determine the
proper timing to begin the next wiper blade sweep.
The normal delay interval is about five seconds.
When the Off position of the multi-function switch
wiper control stalk 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, the intermittent wipe logic circuit de-ener-
gizes the wiper relay, 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 the fused ignition switch output (run-start)
circuit. The intermittent wipe logic circuit energizes
the wiper relay and the wiper on-off relay output cir-
cuit directs battery current to the low speed brush of
the wiper motor through the normally open contact
of the wiper relay, then through the internal Off posi-
tion circuitry of the multi-function switch. This
causes the wiper motor to continue running until the
wiper blades are in the down position on the wind-
shield and the park switch is again closed to ground.
When the Wash position of the control knob on the
right control stalk of the multi-function switch is
selected, the washer switch circuitry directs battery
current to the washer pump motor and to the inter-
mittent wipe logic circuitry. When the washer switch
Fig. 2 Windshield Wiper/Washer Switch
1 - INTERMITTENT WIPE MODE (OR AUTO WIPE MODE IF
EQUIPPED)
2 - CONTINUOUS LOW SPEED WIPE MODE
3 - CONTINUOUS HIGH SPEED WIPE MODE
4 - WASHER MODE
5 - PULSE WIPE MODE
8R - 4 WIPERS/WASHERSVA

CHECK VALVE
DESCRIPTION
A single washer system check valve is standard
equipment on this model, and is installed in the
washer system plumbing (Fig. 4). The check valve is
integral to the washer plumbing fitting located on
the underside of the cowl top panel behind the rear
of the hood panel opening in the engine compart-
ment. The check valve consists of a molded plastic
body with three barbed hose nipples, one at the inlet
side of the valve body and two at the outlet side. The
check valve cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced.
OPERATION
The check valve provides more than one function
in this application. It serves as a plumbing connector
fitting between the engine compartment and washer
nozzle sections of the washer supply hose. It prevents
washer fluid from draining out of the washer supply
hoses back to the washer reservoir. This drain-back
would result in a lengthy delay from when the
washer switch is actuated until washer fluid was dis-
pensed through the washer nozzles, because the
washer pump would have to refill the washer plumb-
ing from the reservoir to the nozzles. Such a drain-
back condition could also result in water, dirt, or
other outside contaminants being siphoned into the
washer system through the washer nozzle orifice.
This water could subsequently freeze and plug the
nozzle, while other contaminants could interfere with
proper nozzle operation and cause improper nozzle
spray patterns. In addition, the check valve prevents
washer fluid from siphoning through the washer noz-
zles after the washer system is turned Off.
When the washer pump pressurizes and pumps
washer fluid from the reservoir through the washer
plumbing, the fluid pressure unseats a diaphragm
from over a sump well within the valve by overridingthe spring pressure applied to it by a piston. With
the diaphragm unseated, washer fluid is allowed to
flow toward the two washer nozzles. When the
washer pump stops operating, the spring pressure on
the piston seats the diaphragm over the sump well in
the valve and fluid flow in either direction within the
washer plumbing is prevented. The check valve can-
not be adjusted or repaired and, if faulty or damaged,
it must be replaced.
REMOVAL
(1) Unlatch and open the hood panel.
(2) Disconnect the washer hoses from the three
barbed nipples of the check valve unit (Fig. 5).
(3) Remove the check valve unit from the under-
side of the cowl top panel.
INSTALLATION
(1) Position the check valve unit to the underside
of the cowl top panel (Fig. 5).
(2) Reconnect the three washer hoses to the
barbed nipples of the check valve unit.
(3) Close and latch the hood.
Fig. 4 Check Valve
1 - INLET NIPPLE
2 - CHECK VALVE
3 - OUTLET NIPPLE (2)
Fig. 5 Check Valve Remove/Install
1 - COWL HOOD SEAL
2 - CHECK VALVE
3 - HOSE TO WASHER NOZZLE (2)
4 - HOSE FROM WASHER PUMP
VAWIPERS/WASHERS 8R - 11