Jeep Grand Cherokee WK. Manual - part 448

Following are descriptions of the how the left multi-function switch operates to control the many interior lighting func-
tions and features it provides:

•

Panel Lamps Dimming - The FCM monitors the left multi-function switch then, based upon that multiplexed
input, provides a variable voltage output through several panel lamps driver circuits to control the lighting of
many incandescent panel lamps. The FCM also sends panel lamps dimming messages over the Controller
Area Network (CAN) data bus to other modules to control display lighting levels in those modules.

•

Interior Lamps Defeat - The FCM monitors the left multi-function switch then, based upon that multiplexed
input, internally disables the function the FCM normally provides to control the illumination of the interior lamps.

•

Parade Mode - The FCM monitors the left multi-function switch then, based upon that multiplexed input, pro-
vides a voltage output through several panel lamps driver circuits to control the lighting of many incandescent
panel lamps. The FCM also sends panel lamps dimming messages over the CAN data bus to other modules
on the bus to control lighting levels in those modules.

•

Interior Lamps On - The FCM monitors the left multi-function switch then, based upon that multiplexed input,
provides a control output to activate all of the interior lamp circuits.

DIAGNOSIS AND TESTING

LEFT MULTI-FUNCTION SWITCH

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental
restraint system before attempting any steering wheel, steering column, airbag, occupant classification sys-
tem, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect
and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge
before performing further diagnosis or service. This is the only sure way to disable the supplemental
restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

The left multi-function switch can be diagnosed using conventional diagnostic tools and methods. However, proper
testing of the multiplexed inputs to the Steering Control Module (SCM) requires the use of a diagnostic scan tool.
(Refer to 19 - STEERING/COLUMN/STEERING CONTROL MODULE - DIAGNOSIS AND TESTING) for the appro-
priate diagnostic information.

REMOVAL

WARNING: On vehicles equipped with airbags, disable the airbag system before attempting any steering
wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the
battery negative (ground) cable, then wait two minutes for the airbag system capacitor to discharge before
performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to
take the proper precautions could result in accidental airbag deployment and possible personal injury.

1. Disconnect and isolate the battery negative cable.

WARNING: Wait two minutes for the airbag system
reserve capacitor to discharge before performing
further diagnosis or service.

2. From below the steering column, remove the three

screws (1) that secure the lower steering column
shroud (2) to the multi-function switch mounting
housing.

3. Using hand pressure, push gently inward on both

sides of the upper shroud (3) near the parting line
between the upper and lower shrouds to release
the snap features that secure the two shroud
halves together.

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LAMPS/LIGHTING - EXTERIOR - SERVICE INFORMATION

4. Remove both the upper and lower shrouds from the steering column.

5. Remove the Steering Control Module (SCM) from

the steering column (Refer to 19 - STEERING/
COLUMN/STEERING COLUMN CONTROL MOD-
ULE - REMOVAL).

6. Remove the two screws that secure the left multi-

function switch (1) to the SCM (2).

7. Disengage the two retaining tabs (3), next to the

screw mounts that secure the left multi-function
switch to the SCM.

8. Disconnect the left multi-function switch from the

SCM.

INSTALLATION

1. Position the left multi-function switch (1) onto posi-

tion on the Steering Control Module (SCM) (2).

2. Engage the two retaining tabs, next to the screw

mounts that secure the left multi-function switch
and firmly snap into place.

3. Install the two screws (3) that secure the left multi-

function switch to the SCM. Tighten the screws to
2.5 N·m (22 in. lbs.).

LAMPS/LIGHTING - EXTERIOR - SERVICE INFORMATION

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4. Position the lower steering column shroud (2) to

the underside of the steering column.

5. Install the three screws (1) that secure the lower

steering column shroud to the multi-function switch
mounting housing. Tighten the screws to 2 N·m (17
in. lbs.).

6. Position the upper column shroud (3) over the

steering column with the hazard warning switch
button inserted through the hole in the upper
shroud.

7. Align the snap features on the upper and lower

shrouds and apply hand pressure to snap them
together.

8. Reconnect the battery negative cable.

PARK/TURN SIGNAL LAMP

REMOVAL

1. Disconnect and isolate the battery negative cable.

2. Remove the headlamp unit (Refer to 8 - ELECTRI-

CAL/LAMPS/LIGHTING - EXTERIOR/HEADLAMP
UNIT - REMOVAL).

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LAMPS/LIGHTING - EXTERIOR - SERVICE INFORMATION

3. Rotate the turn signal bulb socket (4) 1/4 turn

counter clockwise.

4. Remove the bulb socket (4) from the headlamps

unit (5).

5. Remove the bulb from socket.

INSTALLATION

1. Press the bulb into socket.

2. Position the bulb socket (5) into headlamp unit (5).

3. Rotate the turn signal bulb socket (4) 1/4 turn

clockwise.

LAMPS/LIGHTING - EXTERIOR - SERVICE INFORMATION

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