Exterior Lamps
The exterior lighting system consists of the following lamps:
• | The daytime running lamps |
• | The automatic headlamps and park lamps |
• | The park, tail and marker lamps |
Headlamps
The headlamps may be turned ON 2 different ways. First, when the driver
places the headlamp switch in the HEAD position, for normal operation. Second,
with the headlamp switch placed in the AUTO position, during operation in low light
conditions.
On vehicles with manual headlamps, the LH HDLP and RH HDLP fuse in the fuse
block - underhood, supply battery positive voltage to both low beam lamps and
high beam lamps at all times. The low beam and high beam circuits continue through
the fuse block - underhood, through the body control module (BCM), and to the
headlamp switch. The low beam or high beam circuit then, depending on the position
of the dimmer switch, continues through the headlamp switch. When the headlamp switch
is placed in the ON position, it provides a ground path for the low beam or high
beam lamps through G203. The low beam and high beam circuits are monitored by the
BCM.
On vehicles with automatic headlamps, the LH HDLP and RH HDLP fuse in the fuse
block - underhood, supply battery positive voltage to both low beam lamps and
high beam lamps at all times. The low beam and high beam circuits continue through
the fuse block - underhood, through the BCM, and to the headlamp switch. The
low beam or high beam circuit then, depending on the position of the dimmer switch,
continues through the headlamp switch. The low beam and high beam circuits are monitored
by the BCM. During automatic headlamp operation in low light conditions, the BCM will
apply voltage to the coil side of the headlamp relay, energizing it. When the headlamp
relay energizes, it provides a ground path for the low beam or high beam lamps through
G203, depending on the dimmer switch position.
Daytime Running Lamps (DRL)
The front turn signal lamps are used as both daytime running lamps (DRL) and
turn signals lamps. The body control module (BCM) illuminates the front turn signals
lamps in a non flashing mode for DRL operation. If the turn signal switch is activated
during DRL operation, the appropriate turn signal will flash.
On vehicles with automatic headlamps, the DRL are designed to be automatically
illuminated when the ignition is ON and the outside (ambient) light level is high
as in daytime conditions (day mode). The DRL will not operate if the ambient light
levels are too low (night mode). Light levels are detected by the ambient light sensor,
a light sensitive transistor that varies its voltage signal to the BCM in response
to changes to the ambient light level. When the BCM receives a day mode signal from
the ambient light sensor it will then illuminate the DRL lamps. The automatic headlamps
and park lamps will not operate when the DRL lamps are ON.
In the day mode, the ambient light sensor detects daylight and the BCM applies
voltage to the LH and RH front turn signal lamps illuminating the lamps under the
following conditions:
• | The ignition switch is in the RUN position. |
• | The park brake is OFF (released). |
• | The transaxle is not in park. |
• | The RH or LH turn signal is OFF. |
On vehicles with manual headlamps, the DRL are designed to be illuminated when
the ignition is ON and the headlamps are OFF.
When the headlamps are OFF, the BCM applies voltage to the LH and RH front turn
signal lamps illuminating the lamps under the following conditions:
• | The ignition switch is in the RUN position. |
• | The park brake is OFF (released). |
• | The transaxle is not in park. |
• | The RH or LH turn signal is OFF. |
Automatic Headlamps and Park Lamps
The automatic headlamps and park lamps are designed to automatically illuminate
when the ignition is ON and the outside (ambient) light level is low as in night
time conditions (night mode). Light levels are detected by the ambient light sensor,
a light sensitive transistor that varies its voltage signal to the body control module
(BCM) in response to changes to the ambient light level. When the BCM receives a low
light mode signal from the ambient light sensor it will then energize the park lamp
and automatic headlamp relays illuminating the headlamps and park lamps. The daytime
running lamps (DRL) lamps will not operate when the automatic headlamps and park lamps
are ON.
In the low light mode, the ambient light sensor detects low light level, the
BCM turns OFF the front turn signal lamps, and grounds the park lamp relay and automatic
headlamp relay control circuits, turning ON the headlamps and park lamps under the
following conditions:
• | The ignition switch is in the RUN position. |
• | The park brake is OFF (released). |
If the engine stalls with the DRL in the low light mode, the BCM turns OFF
the headlamps while the engine is being cranked. The park lamps will remain ON while
the engine is being cranked.
Fog Lamps
The FOG fuse in the fuse block - underhood supplies battery positive voltage
to the switch side of the fog lamp relay at all times. The coil side of the fog lamp
relay is grounded at G101. When the fog lamp switch is pressed, it pulls the front
fog lamp switch signal circuit low to the body control module (BCM). The BCM then
supplies voltage to the coil side of the fog lamp relay, energizing the relay. The
switch side of the fog lamp relay then supplies voltage to both front fog lamps. The
front fog lamps are connected to ground at G101. The park lamps or headlamps must
be ON for the fog lamps to operate.
Park, Tail and Marker Lamps
The park, tail, and marker lamps, including the license lamps, are illuminated
when the headlamp switch is placed in the PARK or HEAD position. The PARK fuse in
the body control module (BCM) supplies battery positive voltage to the headlamp switch.
When the headlamp switch is placed in the PARK or HEAD position, the headlamp switch
supplies voltage to the park lamp supply voltage circuit. The park lamp supply voltage
circuit goes from the headlamp switch, to the BCM, and then to the park, tail, and
marker lamps. The park, tail, and marker lamps receive a ground at G101, G401, or
G403.
Turn Signal Lamps
When the turn signal switch is place in either the right or left turn position,
the turn/hazard request circuit is pulled low, through a resistor. The body control
module (BCM) uses the resistors to determine if the left or right turn signals have
been requested. The BCM then supplies an ON-OFF voltage to the turn signal
lamps and turn signal indicator on the selected side of the vehicle. The turn signals
receive a ground at G101, G401, or G403.
Hazard Lamps
When the hazard switch is activated, it pulls the turn/hazard request circuit
low. The body control module (BCM) then provides an ON-OFF voltage to all
of the turn signal lamps and both turn signal indicators. The turn signals receive
a ground at G101, G401, or G403.
Stop Lamps
The 15-amp STOP fuse located in the body control module (BCM) supplies
battery positive voltage to the normally open stop lamp switch. When the driver presses
the brake pedal, the switch contacts close and battery positive voltage is supplied
to both left and right stop lamp assemblies and the center high mounted stop lamp
(CHMSL), through the BCM. The stop lamps are grounded at G401 and G403.
Backup Lamps
The 15-amp BACK UP fuse in the fuse block - underhood supplies
ignition positive voltage to the park/neutral position (PNP) switch of an automatic
transmission or the backup lamp switch of a manual transmission. When the transmission
is placed in reverse, the appropriate switch supplies voltage to the backup lamps.
The backup lamps receive ground at G401 and G403.