LIGHTS
SERVICE TOOLS
Description
Fluke 115 multimeter ........................................................... 529 035 868 ................. 258, 260–261, 264
ECM adapter tool.................................................................. 529 036 085 ......................................... 266
GENERAL
LIGHTS SYSTEM DESCRIPTION
The lights system is composed of the following
components:
– Headlight power regulator
– 2 headlights
– A combination taillight/brake light
– "N" neutral indicator light
– Low fuel indicator light
– Check engine indicator light
– Headlight switch.
LIGHTS SYSTEM OPERATION
The lights system receives its power through the
cooling fan/accessories fuse. It is not indepen-
dently fused.
When the engine stop switch is set to "RUN"
and the ignition switch is set to "ON" (with
headlights), the entire lighting system receives
power from the battery, and from the voltage
regulator/rectifier output when the engine is run-
ning.
If the ignition switch is set to "ON" without the
headlights function, only the headlights will not re-
ceive power. This function allows the driver to re-
duce the load on the charging system and battery
when the headlights are not required.
When the electrical load is high and the available
charging system voltage may not be sufficient to
prevent battery power drain, such as when the en-
gine is at idle (or not running), the electrical system
voltage will drop. The headlight power regulator
detects this voltage drop and cycles its output to
the lights to reduce the electrical system load.
The main purpose of the headlight power regulator
is to prevent battery power drainage, saving pow-
er for the essential engine systems. The "low fu-
el" and "check engine" indicator lights are not af-
fected as they are not powered through the head-
light power regulator.
vmr2008-027
Section 06 ELECTRICAL SYSTEM
Subsection 04 (LIGHTS)
Part Number
TROUBLESHOOTING
LIGHTS SYSTEM TESTING
Lights System Testing Sequence
Set engine stop switch to "RUN".
Set ignition switch to "ON" with headlights func-
tion.
The following lights should come on:
– Headlights
– Taillight
– "N" neutral light (if transmission is in neutral)
– Check engine indicator light momentarily (pre-
start test)
– Low fuel level indicator light (only if the fuel is
below the sensor activation level).
None of the Lights Function
IGNITION SYSTEM
Refer to the
Only the Check Engine Light Functions
Test the headlight power regulator.
A Specific Light does not Function
Test the following:
– Applicable bulb
– Light input voltage
– Light control circuit (switches)
– Ground circuit wiring.
Refer to the section applicable to the light not
functioning.
PROCEDURES
HEADLIGHT POWER REGULATOR
Headlight Power Regulator Test
Disconnect the taillight/brake light connector.
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