tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the seatbelt indicator for the following rea-
sons:
• Seatbelt Reminder Function - Each time the
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit, the indica-
tor will be illuminated as a seatbelt reminder for
about seven seconds, or until the ignition switch is
turned to the Off position, whichever occurs first.
This reminder function will occur regardless of the
status of the seatbelt switch input to the cluster.
• Driver Side Front Seatbelt Not Buckled -
Following the seatbelt reminder function, each time
the cluster detects a ground on the seat belt switch
sense circuit (seatbelt switch closed = seatbelt
unbuckled) with the ignition switch in the Start or
On positions, the indicator will be illuminated. The
seatbelt indicator remains illuminated until the seat
belt switch sense input to the cluster is an open cir-
cuit (seatbelt switch open = seatbelt buckled), or
until the ignition switch is turned to the Off position,
whichever occurs first.
• Actuator Test - Each time the cluster is put
through the actuator test, the seatbelt indicator will
be turned on, then off again during the bulb check
portion of the test to confirm the functionality of the
LED and the cluster control circuitry.
The seatbelt switch is connected in series between
ground and the seat belt switch sense input to the
instrument cluster. The seatbelt switch input to the
instrument cluster circuitry can be diagnosed using
conventional diagnostic tools and methods. For fur-
ther diagnosis of the seatbelt indicator or the instru-
ment cluster circuitry that controls the LED, (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING).
SHIFT INDICATOR (TRANSFER
CASE)
DESCRIPTION
A four-wheel drive indicator is standard equipment
on all instrument clusters (Fig. 23). The four-wheel
drive indicator is located near the upper edge of the
instrument cluster, to the right of center. The four-
wheel drive indicator consists of a stencil-like cutout
of the text “4WD” in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. A amber Light Emit-
ting Diode (LED) behind the cutout in the opaque
layer of the overlay causes the “4WD” text to appear
in amber through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The illu-
mination intensity of the four-wheel drive indicator is
one-step dimmable. When the exterior lighting is
turned On, the indicator is dimmed; and, when the
exterior lighting is turned Off, the indicator is illumi-
nated at full intensity. The four-wheel drive indicator
is serviced as a unit with the instrument cluster.
OPERATION
The four-wheel drive indicator gives an indication
to the vehicle operator that a four-wheel drive oper-
ating mode of the four-wheel drive transfer case is
selected. The four-wheel drive indicator lights when
the transfer case is engaged in the 4H or 4L posi-
tions. This indicator is controlled by a transistor on
the instrument cluster electronic circuit board based
upon cluster programming. On models not equipped
with the optional Off-Road Package the cluster also
uses a hard wired transfer case switch input. Models
that are equipped with the Off-Road Package do not
have a hard wired transfer case switch input, so the
cluster uses electronic messages received by the clus-
ter from the Powertrain Control Module (PCM) over
the Programmable Communications Interface (PCI)
data bus to determine the transfer case operating
mode. The four-wheel drive indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the LED will always be off when the ignition switch
is in any position except On or Start. The LED only
illuminates when it is provided a path to ground by
the instrument cluster transistor. The instrument
cluster will turn on the four-wheel drive indicator for
the following reasons:
• Transfer Case Switch Input - Each time the
cluster detects a ground on the 4WD switch sense
circuit (transfer case switch closed = 4WD mode
selected) the part time indicator is illuminated. The
indicator remains illuminated until the 4WD switch
sense input to the cluster is an open circuit (transfer
case switch open = 4WD mode not selected), or until
Fig. 23 4WD Indicator
TJ
INSTRUMENT CLUSTER
8J - 37
SEATBELT INDICATOR (Continued)