Jeep 1997 Grand Cherokee Service Manual page 472

8J - 2 TURN SIGNAL AND HAZARD WARNING SYSTEMS
DESCRIPTION AND OPERATION (Continued)
If supplemental lighting is added to the turn signal
lamp circuits, such as when towing a trailer with
lights, the combination flasher will automatically
compensate. This allows the flash rate to remain the
same, regardless of electrical load increases. How-
ever, if a bulb fails in the turn signal lamp circuits,
the flash rate of the remaining bulbs in that circuit
will increase to 120 flashes-per-minute, or higher.
While the combination flasher shares the terminal
orientation (footprint) of a International Standards
Organization (ISO)-type relay, the internal circuitry
is much different. The combination flasher contains
active electronic integrated circuitry elements. Do not
substitute any other relay for the combination
flasher.
Because of the active electronic elements within
the combination flasher, it cannot be tested with con-
ventional automotive electrical test equipment. If the
combination flasher is believed to be faulty, test the
turn signal and hazard warning system circuits as
described in this group. Then replace the combina-
tion flasher with a known good unit to confirm sys-
tem operation.
The combination flasher cannot be repaired and, if
faulty, it must be replaced.
TURN SIGNAL SWITCH AND HAZARD WARNING
SWITCH
The turn signal and hazard warning switches are
integral to the multi-function switch assembly. The
multi-function switch assembly is secured to the left
side of the steering column (Fig. 1). This switch con-
tains circuitry for the following functions:
• Turn signals
• Hazard warning
• Headlamp beam selection
• Headlamp optical horn
• Windshield wipers
• Windshield washers.
The information contained in this group addresses
only the multi-function switch functions for the turn
signal and hazard warning circuits. For information
relative to the other switch functions, refer to the
proper group. However, the multi-function switch
cannot be repaired. If any function of the multi-func-
tion switch is faulty, or if the switch is damaged, the
entire switch assembly must be replaced.
TURN SIGNAL INDICATOR LAMP
The turn signal indicator lamps are located in the
instrument cluster. They flash with the exterior turn
signal lamps to give the driver a visual indication
that a turn signal or the hazard warning system is
operating. For diagnosis and service of these lamps,
refer to Group 8E - Instrument Panel Systems.
WINDSHIELD WASHER BUT- WINDSHIELD WIPER CON- TON TROL
Fig. 1 Multi-Function Switch
VEHICLE INFORMATION CENTER
Models equipped with an optional Vehicle Informa-
tion Center (VIC) have a "turn signal on" warning
feature. The VIC module monitors the turn signal
circuit from the combination flasher. The VIC module
will display the message, Turn Signal On, and send a
request to the Body Control Module (BCM) on the
Chrysler Collision Detection (CCD) data bus network
for six chime tones, if a turn signal remains activated
for more than approximately one-half mile of driving.
Refer to Group 8E - Instrument Panel Systems for
diagnosis and service of the VIC module. Refer to the
proper Body Diagnostic Procedures manual for diag-
nosis and service of the BCM or the CCD data bus.
TURN SIGNAL LAMP
The exterior lamps in the turn signal and hazard
warning circuits include the front park/turn signal,
the front side marker, and the rear tail/stop/turn sig-
nal. For diagnosis and service of these lamps, refer to
Group 8L - Lamps.
DIAGNOSIS AND TESTING
INTRODUCTION
When diagnosing the turn signal or hazard warn-
ing circuits, remember that high generator output
can burn out bulbs rapidly and repeatedly. If this is a
problem on the vehicle being diagnosed, refer to
Group 8C - Charging System for further diagnosis of
a possible generator overcharging condition.
CONTROL STALK H AZARD WARNING BUTTON MULTI-FUNCTION SWITCH
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