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VA
BRAKE WEAR INDICATOR (Continued)
illuminated by the instrument cluster for about two
seconds as a bulb test.
• Brake Wear Sensor Input - Each time the
cluster detects ground on the brake wear sense cir-
cuit (brake wear sensor closed = brake lining wear
limit exceeded) while the ignition switch is in the On
position, the brake wear indicator is illuminated. The
indicator remains illuminated until the brake wear
sense input to the cluster is an open circuit (brake
wear sensor open = brake lining wear within limits),
or until the ignition switch is turned to the Off posi-
tion, whichever occurs first.
A brake wear sensor located at each wheel provides
a hard wired ground input to the instrument cluster
circuitry through the brake wear sense circuit when-
ever the brake linings for that wheel have exceeded
their wear limits. The four normally open brake wear
sensors are connected in parallel between ground and
instrument cluster. The brake wear sensors and their
input circuit to the instrument cluster can be diag-
nosed using conventional diagnostic tools and meth-
ods. For proper diagnosis of the instrument cluster
circuitry that controls the brake wear indicator, a
DRBIII scan tool is required. Refer to the appropri-
ate diagnostic information.
CHARGING INDICATOR
DESCRIPTION
A charging indicator is standard equipment on all
instrument clusters. The charging indicator is located
near the lower edge of the instrument cluster, to the
left of the multi-function indicator display. The
charging indicator consists of the International Con-
trol and Display Symbol icon for "Battery Charging
Condition" imprinted within a rectangular cutout in
the opaque layer of the instrument cluster overlay.
The dark outer layer of the overlay prevents the indi-
cator from being clearly visible when it is not illumi-
nated. A red Light Emitting Diode (LED) behind the
cutout in the opaque layer of the overlay causes the
icon to appear silhouetted against a red field 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 elec-
tronic circuit board. The charging indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The charging indicator gives an indication to the
vehicle operator when the electrical system voltage is
too low. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and a hard wired input from the
generator. The charging indicator Light Emitting
INSTRUMENT CLUSTER 8J - 13
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 detects that the ignition switch is in the On
position. Therefore, the LED will always be off when
the ignition switch is in any position except On. The
LED only illuminates when it is provided a path to
ground by the instrument cluster transistor. The
instrument cluster will turn on the charging indica-
tor for the following reasons:
• Bulb Test - Each time the ignition switch is
turned to the On position with the engine not run-
ning the charging indicator is illuminated by the
instrument cluster as a bulb test.
• Generator Input - Each time the cluster
detects that the voltage of the generator input is 12.7
volts or lower while the engine is running, the charg-
ing indicator will be illuminated. The indicator
remains illuminated until the cluster detects that the
voltage of the generator input is above 12.7 volts, or
until the ignition switch is turned to the Off position,
whichever occurs first.
The generator provides a hard wired input to the
instrument cluster circuitry on the engine running
(D+) circuit. If the instrument cluster turns on the
indicator while the engine is running, it may indicate
that the charging system requires service. The gener-
ator input circuit to the instrument cluster can be
diagnosed using conventional diagnostic tools and
methods. For proper diagnosis of the charging sys-
tem, or the instrument cluster circuitry that controls
the charging indicator, a DRBIII
required. Refer to the appropriate diagnostic infor-
mation.
CLOCK
DESCRIPTION
An electronic digital clock is standard equipment
on all instrument clusters. In vehicles equipped with
the optional ambient temperature indicator, the clock
indication can be toggled with the ambient tempera-
ture indication on the right side of the multi-function
indicator Liquid Crystal Display (LCD) located near
the lower edge of the instrument cluster, directly
below the speedometer. The clock provides a 12 hour-
based, digital indication of the current hours and
minutes. The indications of the clock are not visible
when the LCD is not illuminated. When illuminated
the indications appear as dark characters silhouetted
against an amber field. When the exterior lighting is
turned Off, the display is illuminated at maximum
brightness. When the exterior lighting is turned On
the display illumination level can be adjusted in con-
cert with the cluster general illumination lighting
scan tool is
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