CARGO LAMP INDICATOR
DESCRIPTION
A cargo lamp indicator is standard equipment on all
instrument clusters. The cargo lamp indicator is
located on the right side of the instrument cluster, to
the right of the oil pressure gauge.
The cargo lamp indicator consists of a stencil-like cutout of the words “CARGO LAMP” 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. An amber Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay
causes the “CARGO LAMP” 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 cargo lamp indicator is serviced as a unit with the instrument cluster.
OPERATION
The cargo lamp indicator gives an indication to the vehicle operator when the exterior cargo lamp is illuminated.
This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming,
a hard wired multiplex input received by the cluster from the panel lamps dimmer switch on the headlamp dimmer
switch mux circuit, and electronic unlock request messages received from the optional Remote Keyless Entry (RKE)
module.
The cargo lamp indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit,
and that logic will only allow this indicator to operate whenever 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 cargo lamp indicator for the following reasons:
•
Cargo Lamp-On Input - Each time the cluster detects a cargo lamp-on input from the headlamp switch on the
headlamp dimmer switch mux circuit, the cargo lamp and the cargo lamp indicator will be illuminated. The
cargo lamp and indicator remain illuminated until the cluster receives a cargo lamp-off input from the headlamp
switch, until the cluster has completed an interior lamps load shed (about five minutes), 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 cargo lamp 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 instrument cluster continually monitors the headlamp dimmer switch circuit to determine the proper interior
lamps features and panel lamps illumination levels to provide. The cluster then energizes and de-energizes a low
side driver circuit to control the exterior cargo lamp. Each time the instrument cluster energizes the cargo lamp
driver and the ignition switch is in the On or Start positions, the cluster also turns on the cargo lamp indicator. For
further diagnosis of the cargo lamp indicator or the instrument cluster circuitry that controls the indicator, (Refer to
8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the cargo lamp or the headlamp switch inputs to the instrument cluster that control the
cargo lamp indicator, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.
CHECK GAUGES INDICATOR
DESCRIPTION
A check gauges indicator is standard equipment on all
instrument clusters. On vehicles equipped with a gas-
oline engine, the check gauges indicator is located
near the lower edge of the instrument cluster, between the tachometer and the speedometer. On vehicles equipped
8J - 120
INSTRUMENT CLUSTER -SERVICE INFORMATION
DR/DH