CHARGING INDICATOR
DESCRIPTION
A charging indicator is standard equipment on all
instrument clusters. This indicator is located near the
upper edge of the instrument cluster, between the
tachometer and the speedometer.
The charging indicator consists of a stencil-like cutout of the International Control and Display Symbol icon for “Bat-
tery Charging Condition” in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay
prevents the indicator from being clearly visible when it is not illuminated. A red Light Emitting Diode (LED) behind
the cutout in the opaque layer of the overlay causes the icon to appear in red 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 charging indicator is serviced 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 or
too high. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster pro-
gramming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the
Controller Area Network (CAN) data bus.
The charging indicator Light Emitting Diode (LED) is completely controlled by the instrument 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 charging indicator for the following reasons:
•
Bulb Test - Each time the ignition switch is turned to the On position the charging indicator is illuminated by
the instrument cluster for about two seconds as a bulb test.
•
Voltage Low Message - Each time the cluster receives a message from the PCM indicating the electrical
system voltage is low (less than about 11.5 volts is a charge fail condition), the charging indicator will be illu-
minated. The indicator remains illuminated until the cluster receives a message from the PCM indicating the
electrical system voltage is normal (greater than about 12.0 volts, but less than 16.0 volts), or until the ignition
switch is turned to the Off position, whichever occurs first.
•
Voltage High Message - Each time the cluster receives a message from the PCM indicating the electrical
system voltage is high (greater than about 16.0 volts), the charging indicator will be illuminated. The indicator
remains illuminated until the cluster receives a message from the PCM indicating the electrical system voltage
is normal (less than about 15.5 volts, but greater than 11.5 volts), 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 charging 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 PCM continually monitors the electrical system voltage to control the generator output. The PCM then sends
the proper system voltage messages to the instrument cluster. If the instrument cluster turns on the charging indi-
cator due to a charge fail or voltage high condition, it may indicate that the charging system requires service. For
further diagnosis of the charging indicator or the instrument cluster circuitry that controls the indicator, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the charging system, the PCM, the CAN data bus, or the electronic message inputs to the
instrument cluster that control the charging indicator, a diagnostic scan tool is required. Refer to the appropriate
diagnostic information.
8J - 54
CLUSTER
ND