Jeep Grand Cherokee WJ. Manual - part 120

safety equipment on this model. The turn signal sys-
tem allows the vehicle operator to provide the drivers
of other vehicles in near proximity with an optical
indication of his intention to perform a turning
maneuver or to change traffic lanes. The turn signal
system uses ignition switched battery current, and
will operate only when the ignition switch is in the
On position.

Vehicles equipped with the optional Electronic

Vehicle Information Center (EVIC) have a Turn Sig-
nal On warning feature. This feature is designed to
provide the driver with both visual and audible
reminders when a turn signal has been left turned
on for an extended period. Refer to Electronic Vehi-
cle Information Center in the Description and
Operation section of Group 8V - Overhead Console
Systems for more information on the EVIC features.

The turn signal system includes the following com-

ponents:

• Combination flasher

• Front side marker lamps

• Turn signal cancelling cam

• Turn signal indicator lamps

• Turn signal lamps

• Turn signal switch.
Refer to Lamp in the proper section of Group 8L -

tor lamps. Following are general descriptions of the
major components in the turn signal system. For
complete circuit diagrams, refer to Turn Signals in
the Contents of Group 8W - Wiring Diagrams.

OPERATION

With the ignition switch in the On or Accessory

position, and the turn signal (left or lighting multi-
function) switch control stalk moved up (right turn)
or down (left turn), the turn signal system is acti-
vated. When the turn signal system is activated, the
circuitry of the turn signal switch and the combina-
tion flasher will cause the selected (right or left) turn
signal indicator lamp, front park/turn signal lamp,
front side marker lamp, and rear turn signal lamp to
flash on and off. If the exterior lighting is turned off,
the front park/turn signal lamp and the front side
marker lamp will flash in unison. If the exterior
lighting is turned on, the front park/turn signal lamp
and the front side marker lamp will flash alternately.

The EVIC module uses turn signal status messages

from

the

Electro-Mechanical

Instrument

Cluster

(EMIC) module and distance messages from the Pow-
ertrain Control Module (PCM) received over the Pro-
grammable Communications Interface (PCI) data bus
network to determine when the Turn Signal On
warning should be activated. The EMIC receives a
hard wired input from the combination flasher to
determine the proper turn signal status message to
send. If a turn signal is left on for more than about
1.6 kilometers (1 mile) of driving distance, the EVIC
will display the Turn Signal On message and will
send a request to the Body Control Module (BCM)
over the PCI data bus for two sets of three chime
tones to sound.

TURN SIGNAL AND HAZARD WARNING SYSTEMS

8J - 1

See the owner’s manual in the vehicle glove box for

more information on the features, use and operation
of the turn signal system.

HAZARD WARNING SYSTEM

DESCRIPTION

A hazard warning system is standard factory-in-

stalled safety equipment on this model. The hazard
warning system allows the vehicle operator to pro-
vide the drivers of other vehicles in near proximity
an optical indication that the vehicle is disabled or is
an obstacle to traffic flow. Unlike the turn signal sys-
tem, the hazard warning system uses a non-switched
source of battery current so that the system will
operate regardless of the ignition switch position.

The hazard warning system can also be activated

by the Body Control Module (BCM). The BCM is pro-
grammed to activate the hazard warning system
lamps in order to provide the following features:

• Remote Keyless Entry (RKE) system lock and

unlock request optical verification (customer pro-
grammable)

• RKE system panic mode optical alert

• Vehicle Theft Security System (VTSS) optical

alarm.

This vehicle also offers several customer program-

mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences. Refer to ELECTRONIC VEHICLE INFOR-
MATION

CENTER

PROGRAMMING

the

Service Procedures section of Group 8V - Overhead
Console Systems for more information on the cus-
tomer programmable feature options. Customer pro-
grammable feature options affecting the hazard
warning system include:

• Flash Lights with Lock - Allows the option of

having the lights flash as an optical verification that
the RKE system received a valid Lock request or
Unlock request from the RKE transmitter, or having
no optical verification.

The hazard warning system includes the following

components:

• Combination flasher

• Front side marker lamps

• Hazard warning switch

• Turn signal indicator lamps

• Turn signal lamps.
Certain functions and features of the horn system

rely upon resources shared with other electronic
modules in the vehicle over the Programmable Com-
munications Interface (PCI) data bus network. The
PCI data bus network allows the sharing of sensor
information. This helps to reduce wire harness com-
plexity, internal controller hardware, and component
sensor current loads. At the same time, this system

provides increased reliability, enhanced diagnostics,
and allows the addition of many new feature capabil-
ities. For diagnosis of these electronic modules or of
the PCI data bus network, the use of a DRB scan
tool and the proper Diagnostic Procedures manual
are recommended.

The other electronic modules that may affect haz-

ard warning system operation are as follows:

• Body Control Module (BCM) - Refer to Body

Control Module in the Description and Operation
section of Group 8E - Instrument Panel Systems for
more information.

•

Electronic

Vehicle

Information

Center

(EVIC) - Refer to Electronic Vehicle Information
Center in the Description and Operation section of
Group 8V - Overhead Console Systems for more
information.

Refer to Lamp in the proper section of Group 8L -

Lamps for more information on the exterior turn sig-
nal lamps. Refer to Instrument Cluster in the
proper section of Group 8E - Instrument Panel Sys-
tems for more information on the turn signal indica-
tor lamps. Following are general descriptions of the
major components in the hazard warning system. For
complete circuit diagrams, refer to Turn Signals in
the Contents of Group 8W - Wiring Diagrams.

OPERATION

With the hazard warning switch in the On posi-

tion, the hazard warning system is activated. When
the hazard warning system is activated, the circuitry
of the hazard warning switch and the combination
flasher will cause both the right side and the left side
turn signal indicator lamps, front park/turn signal
lamps, front side marker lamps and rear turn signal
lamps to flash on and off. If the exterior lamps are
turned off, the front park/turn signal lamps and the
front side marker lamps will flash in unison. If the
exterior lamps are turned on, the front park/turn sig-
nal lamps and the front side marker lamps will flash
alternately.

The BCM can also activate the hazard warning

system lamps by energizing the electronic combina-
tion flasher through a single hard wired output cir-
cuit. The BCM energizes and de-energizes the
combination flasher in response to internal program-
ming as well as message inputs received over the
Programmable Communications Interface (PCI) data
bus network. The BCM can energize the combination
flasher for a single flash (RKE lock request), several
flashes (RKE unlock request), or for extended opera-
tion (RKE panic mode and VTSS alarm mode).

See the owner’s manual in the vehicle glove box for

more information on the features, use and operation
of the hazard warning system.

8J - 2

TURN SIGNAL AND HAZARD WARNING SYSTEMS

DESCRIPTION AND OPERATION (Continued)

TURN SIGNAL SWITCH AND HAZARD
WARNING SWITCH

DESCRIPTION

The turn signal and hazard warning switches are

integral to the left (lighting) multi-function switch
unit, which is secured to the left side of the multi-
function switch mounting housing at the top of the
steering column (Fig. 1). The only visible parts of the
left multi-function switch are the control stalk that
extends from the left side of the steering column, and
the hazard warning switch push button that pro-
trudes from the top of the steering column. The left
multi-function switch control stalk has both nomen-
clature and international control symbols on it,
which identify its many functions. The hazard warn-
ing switch push button is identified with a double tri-
angle, which is the international control symbol for
hazard warning. The remainder of the left multi-
function switch is concealed beneath the steering col-
umn shrouds.

The left multi-function switch also contains cir-

cuitry for the following functions:

• Exterior lighting control, including:

• Fog lamps

• Park lamps

• Headlamps

• Auto headlamps (if equipped)

• Headlamp beam selection

• Headlamp optical horn.

• Interior lighting control, including:

• Interior lamps defeat

• Interior lamps on

• Panel lamps dimming.
The information contained in this group addresses

only the left multi-function switch turn signal and
hazard warning functions. For information relative to
the other systems that are controlled by and circuits
that are integral to the left multi-function switch, see
the group in this service manual that covers that sys-
tem. However, the turn signal and hazard warning
switches cannot be repaired. If these switches or any
other circuit or component of the left multi-function
switch unit is faulty or damaged, the entire left
multi-function switch unit must be replaced.

OPERATION

TURN SIGNAL SWITCH

The left multi-function switch control stalk that

extends from the left side of the steering column just
below the steering wheel is moved up or down to
activate the turn signal switch. When the control
stalk is moved in the upward direction, the right
turn signal switch circuitry is activated; and, when
the control stalk is moved in the downward direction,

the left turn signal switch circuitry is activated. The
turn signal switch has a detent position in each
direction that provides turn signals with automatic
cancellation, and an intermediate momentary posi-
tion in each direction that provides turn signals only
until the left multi-function switch control stalk is
released.

When the turn signal switch is in a detent posi-

tion, it is turned off by one of two lobes of the turn
signal cancelling cam, which is located beneath the
clockspring mechanism within the multi-function
switch mounting housing on the steering column.
Turning the steering wheel causes the turn signal
cancelling cam lobes to contact a cancel actuator in
the left multi-function switch, and the turn signal
switch automatically returns to the off position.

HAZARD WARNING SWITCH

The hazard warning switch is controlled by the

hazard warning switch push button. Push the switch
button in to unlatch the switch and activate the haz-
ard warning system, and push in on the button again
to latch the switch and turn the system off. When
the hazard warning switch is latched (hazard warn-
ing off), the push button will be in a lowered position
on the top of the steering column shroud; and, when
the hazard warning switch is unlatched (hazard
warning on), the push button will be in a raised posi-
tion.

Fig. 1 Left (Lighting) Multi-Function Switch

1 – EXTERIOR LIGHTING CONTROL
2 – INTERIOR LIGHTING CONTROL
3 – CONTROL STALK
4 – HAZARD WARNING BUTTON
5 – CANCEL ACTUATOR
6 – LEFT (LIGHTING) MULTI-FUNCTION SWITCH

TURN SIGNAL AND HAZARD WARNING SYSTEMS

8J - 3

DESCRIPTION AND OPERATION (Continued)

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