Ford 2003 Mustang Workshop Manual page 3516

Is the voltage greater than 10 volts?
A5 CHECK THE DRL MODULE GROUND — CIRCUIT 1205
(BK)
Measure the resistance between DRL module C1030 Pin
4, Circuit 1205 (BK), harness side and ground.
Is the resistance less than 5 ohms?
A6 CHECK THE HIGH BEAM DISABLE INPUT CIRCUIT FOR
SHORT TO BATTERY — CIRCUIT 12 (LG/BK)
Measure the voltage between DRL module C1030 Pin 5,
Circuit 12 (LG/BK), harness side and ground.
Is voltage indicated?
PINPOINT TEST B: THE DAYTIME RUNNING LAMPS ARE ON WITH
THE PARKING BRAKE SET
B1 CHECK THE PARKING BRAKE SWITCH
Key in OFF position.
Disconnect: Parking Brake Switch C306.
Connect a 10A fused jumper wire between parking brake
switch C306, Circuit 22 (LB/BK), harness side and ground.
Key in ON position.
Test Step
Yes
GO to A6 .
No
REPAIR the circuit. TEST the
system for normal operation.
Yes
REPAIR the circuit. TEST the
system for normal operation.
No
INSTALL a new DRL module.
REFER to Module—Daytime
Running Lamps (DRL)
the system for normal
operation.
Result / Action to Take
Yes
INSTALL a new parking
brake signal switch and
bracket. TEST the system
for normal operation.
No
GO to B2 .
. TEST