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Symptom Chart
Pinpoint Tests
CAUTION: Before removing and installing the GEM or its connectors, disconnect the Output Circuit Failure
B2488 RF Side Repeater Lamp
Output Circuit Failure GEM REFER to
Section 417 - 01 .
C1189 Brake Fluid Level Sensor
Input Short Circuit to Ground GEM REFER to
Section 413 - 01 .
C1223 Lamp Brake Warning
Output Circuit Failure GEM REFER to
Section 413 - 01 .
C1225 Lamp Brake Warning
Output Circuit Short to
Battery GEM REFER to
Section 413 - 01 .
Symptom Chart Condition
Possible Sources Action
z No communication with the generic
electronic module z
CJB Fuse 39
(5A)
z GEM.
z Circuitry. z
GO to
Pinpoint Test A .
z The courtesy lamps are inoperative zCJB Fuse 7
(20A).
z Door ajar switch
(es).
z Courtesy lamp
assemblies.
z Circuitry.
z GEM.
z Ignition Switch.
z Headlamp
Switch. z
GO to
Pinpoint Test B .
z The demand lighting is inoperative zCJB Fuse 7
(20A).
z Circuitry.
z GEM.
z Door ajar switch
(es).
z Demand lamp
assemblies.
z Ignition Switch.
z Headlamp
Switch. z
GO to
Pinpoint Test C .
z The illuminated entry is inoperative
when using the remote transmitter z
Remote
transmitter.
z GEM. z
GO to
Pinpoint Test D .
z The battery saver does not
deactivate after timeout z
Circuitry.
z GEM. z
GO to
Pinpoint Test E . Klj . 5 ba
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DIAGNOSIS AND TESTING
Daytime Running Lamps (DRL)
Refer to Wiring Diagrams Cell
97 , Daytime Running Lamps for schematic and connector information.
Principles of Operation
Daytime Running Lamps (DRL)
The daytime running lamps (DRL) system operates the low beam headlamps at a reduced intensity.
The DRL module (15A270) supplies pulse width modulated (PWM) voltage, approximately 75%- 92%
of battery voltage, to the low beam headlamps when the following conditions are met:
zThe parking brake control is released.
z The high beam headlamps are disabled.
z The ignition switch (11572) is in the RUN position.
The DRL module remains enabled when the low beam headlamps are turned on.
Inspection and Verification 1. Verify the customer concern by operating the system.
2. Visually inspect for obvious signs of mechanical and electrical damage.
3. Verify the headlamps are operating correctly. Correct any concerns before proceeding to the
SECTION 417-
04: Daytime Running Lamps 2003 Mustang Workshop Manual Special Tool(s)
73III Automotive Meter or
equivalent
105-
R0057
Visual Inspection Chart Mechanical Electrical
z
Damaged DRL module
z Damaged parking brake signal switch and
bracket (15A851) z
Blown battery junction box (BJB) Maxi-
Fuse FOG+DRL (20A)
z Damaged wiring harness
z Loose or corroded connection
z Damaged DRL module
z Damaged parking brake signal switch and
bracket Klj . 1 ba
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next step. For additional information, refer to
Section 417 - 01 .
4. Verify the parking brake control is fully released.
5. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
6. If the concern is not visually evident, verify the symptom and refer to the Symptom Chart.
Symptom Chart
Pinpoint Tests
PINPOINT TEST A: THE DAYTIME RUNNING LAMPS ARE
INOPERATIVE Symptom Chart Condition
Possible Sources Action
z The daytime running lamps are
inoperative z
BJB Maxi- Fuse
FOG+DRL (20A).
z Circuitry.
z Parking brake
signal switch and
bracket.
z DRL module. z
GO to
Pinpoint Test A .
z The daytime running lamps are
on with the parking brake set z
Circuitry.
z Parking brake
signal switch and
bracket.
z DRL module. z
GO to
Pinpoint Test B .
z The daytime running lamps are
on with the ignition switch off z
Circuitry.
z Ignition switch.
z DRL module. z
GO to
Pinpoint Test C .
z The low beam headlamps are on
at full intensity in DRL mode z
Circuitry.
z Headlamp switch.
z DRL module. z
GO to
Pinpoint Test D .
z The low beam headlamps are on
at reduced intensity with the
headlamp switch on z
Circuitry.
z Headlamp switch. z
REFER to
Section 417 -
01 .
Test Step Result / Action to Take
A1 CHECK THE PARKING BRAKE SWITCH SIGNAL
CIRCUIT TO THE DRL MODULE FOR SHORT TO GROUND NOTE:
Verify the parking brake control is fully released
for this step.
z Key in OFF position.
z Disconnect: DRL Module C1030.
z Measure the resistance between DRL module C1030 Pin
6, Circuit 22 (LB/BK), harness side and ground. Yes
GO to
A3 .
No
GO to A2 . Klj . 2 ba
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