DOOR AJAR INDICATOR
DESCRIPTION
A door ajar indicator is standard equipment on all
instrument
clusters.
However,
on
vehicles
not
equipped with this optional feature, this indicator is
electronically disabled. The door ajar indicator is
located in the Information Center area of the instru-
ment cluster, to the left of center. The door ajar indi-
cator consists of a stenciled cutout of the words
“DOOR AJAR” 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 lens behind the cut-
out in the opaque layer of the overlay causes the
“DOOR AJAR” text to appear in red through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by a Light Emitting
Diode (LED) soldered onto the instrument cluster
electronic circuit board. The door ajar indicator is
serviced as a unit with the instrument cluster.
OPERATION
The door ajar indicator gives an indication to the
vehicle operator that one or more of the passenger
compartment doors may be open or not completely
latched. This indicator is controlled by a transistor
on the instrument cluster circuit board based upon
cluster
programming
and
electronic
messages
received by the cluster from the Central Timer Mod-
ule (CTM) over the Programmable Communications
Interface (PCI) data bus. The door ajar indicator
Light Emitting Diode (LED) receives battery current
on the instrument cluster electronic circuit board
through the fused ignition switch output (run-start)
circuit whenever the ignition switch is in the On or
Start positions; 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 pro-
vided a path to ground by the instrument cluster
transistor. The instrument cluster will turn on the
door ajar indicator for the following reasons:
• Bulb Test - Each time the ignition switch is
turned to the On position the door ajar indicator is
illuminated for about two seconds as a bulb test.
• Door Ajar Lamp-On Message - Each time the
cluster receives a door ajar lamp-on message from
the CTM indicating that a door is open or not com-
pletely latched, the door ajar indicator will be illumi-
nated. The indicator remains illuminated until the
cluster receives an door ajar lamp-off message from
the CTM, 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 door ajar indicator will
be turned on, then off again during the bulb check
portion of the test to confirm the functionality of the
cluster control circuitry.
The CTM continually monitors the door ajar
switches to determine the status of the doors. The
CTM then sends the proper door ajar lamp-on and
lamp-off messages to the instrument cluster. For fur-
ther diagnosis of the door ajar indicator or the
instrument cluster circuitry that controls the indica-
tor,
(Refer
to
8
-
ELECTRICAL/INSTRUMENT
CLUSTER
-
DIAGNOSIS AND
TESTING).
For
proper diagnosis of the door ajar switches and cir-
cuits, (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING
- INTERIOR/DOOR AJAR SWITCH - DIAGNOSIS
AND TESTING). For proper diagnosis of the CTM,
the PCI data bus, or the message inputs to the
instrument cluster that control the door ajar indica-
tor, a DRBIII
t scan tool is required. Refer to the
appropriate diagnostic information.
ENGINE TEMPERATURE
GAUGE
DESCRIPTION
An engine coolant temperature gauge is standard
equipment on all instrument clusters. The engine
coolant temperature gauge is located in the lower left
quadrant of the instrument cluster, below the voltage
gauge. The engine coolant temperature gauge con-
sists of a movable gauge needle or pointer controlled
by the instrument cluster circuitry and a fixed 90
degree scale on the cluster overlay that reads left-to-
right from “C” (or Cold) to “H” (or Hot) for all
engines. An International Control and Display Sym-
bol icon for “Engine Coolant Temperature” is located
on the cluster overlay, in the center of the gauge
directly above the hub of the gauge needle. The
engine coolant temperature gauge graphics are white
against a black field except for a single red gradua-
tion at the high end of the gauge scale, making them
clearly visible within the instrument cluster in day-
light. When illuminated from behind by the panel
lamps dimmer controlled cluster illumination lighting
with the exterior lamps turned On, the white graph-
ics appear blue-green and the red graphics appear
red. The orange gauge needle is internally illumi-
nated. Gauge illumination is provided by replaceable
incandescent bulb and bulb holder units located on
the instrument cluster electronic circuit board. The
engine coolant temperature gauge is serviced as a
unit with the instrument cluster.
OPERATION
The engine coolant temperature gauge gives an
indication to the vehicle operator of the engine cool-
ant temperature. This gauge is controlled by the
8J - 18
INSTRUMENT CLUSTER
AN