Dodge ram truck 3500 1996 Service Manual page 474

8J - 2 TURN SIGNAL AND HAZARD WARNING SYSTEMS B R
DESCRIPTION AND
O P E R A T I O N fContinued)
bimetal strip is attached between the two arms.
When the hazard warning switch is activated, cur­
rent flows through the flasher. As the current flows
through the bimetal strip it heats and pulls the mov­
able arms together until the contact points close,
allowing current flow to the lamps. As the bimetal
strip cools, the contact points are pushed open and
the cycle repeats.
MULTI-FUNCTION SWITCH
The multi-function switch assembly is mounted to
the left side of the steering column (Fig. 1). This
switch contains 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 switch functions for the turn signal and haz­
ard warning circuits. For information relative to the
other switch functions, refer to the appropriate
group. However, the multi-function switch cannot be
repaired. I f any function of the switch is faulty, the
entire switch assembly must be replaced.
HAZARD WARNING
J938J-3
Fig. 1 Multi-Function Switch
TURN SIGNAL INDICATOR LAMPS
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 this compo­
nent, refer to Group 8E - Instrument Panel Systems.
TURN SIGNAL LAMPS
The exterior lamps in the turn signal and hazard
warning circuits include the front park/turn signal,
and the rear tail/stop/turn signal. For diagnosis and
service of these lamps, refer to Group 8L - Lamps.
D I A G N O S I S A N D T E S T I N G
INTRODUCTION
When diagnosing the turn signal or hazard warn­
ing circuits, remember that high generator output
can burn out bulbs rapidly and repeatedly. I f this is a
problem on the vehicle being diagnosed, refer to
Group 80 - Charging System for further diagnosis.
WARNING: ON VEHICLES EQUIPPED WITH AN AIR-
BAG, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING
WHEEL OR STEERING COLUMN COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI­
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
TURN SIGNAL SYSTEM
For circuit descriptions and diagrams, refer to
8W-52 - Turn Signals in Group 8W - Wiring Dia­
grams.
(1) Turn the ignition switch to the On position.
Move the turn signal lever down for a left turn signal
problem, or up for a right turn signal problem.
Observe the turn signal indicator lamp in the instru­
ment cluster. I f the lamp lights but does not flash,
check for an exterior turn signal lamp that is not lit.
Replace the faulty bulb or repair the circuits to that
lamp, as required. Test the turn signal operation
again. I f the turn signal indicator lamp does not light
or still doesn't flash, go to Step 2.
(2) Check the fuse in the fuseblock module. I f OK,
go to Step 3. I f not OK, replace the faulty fuse.
(3) With the ignition switch i n the On position,
check for battery voltage at the fuse in the fuseblock
module. I f OK, go to Step 4. I f not OK, repair the
open circuit as required.
(4) With the ignition switch in the On position,
place the turn signal lever in the neutral position.
There should be battery voltage at the fused ignition
switch output circuit cavity for the turn signal
flasher. I f OK, go to Step 5. I f not OK, repair the
open circuit as required.
(5) Replace the turn signal flasher with a known
good unit of the same rating. The lamps should flash.
I f OK, discard the faulty flasher. I f not OK, re-install
the original flasher and go to Step 6.