Ford 2003 Mustang Workshop Manual page 3400

D8 CHECK FOR POWER TO THE AFFECTED SUBWOOFER
AMPLIFIER
Key in OFF position.
Disconnect: Mach 1000 Affected Subwoofer Amplifier.
Measure the voltage between affected subwoofer amplifier pin 5,
circuit 828 (VT/LB) (left amplifiers) and ground, or between pin 5,
circuit 829 (WH/VT) (right amplifiers) and ground.
Is the voltage greater than 10 volts?
D9 CHECK FOR GROUND TO THE AFFECTED SUBWOOFER
AMPLIFIER
NOTE: Ground circuit 694 is located in the same cavity in all four
subwoofer amplifiers.
Measure the resistance between affected subwoofer amplifier pin 2,
circuit 694 (BK/LG) and ground.
Is the resistance less than 5 ohms?
D10 CHECK FOR AN AUDIO SIGNAL TO THE AFFECTED
SUBWOOFER AMPLIFIER
Key in ON position.
NOTE: Audio signal circuits 169 and 172 are located in the same
cavity on all four subwoofer amplifiers.
Turn on the audio unit and check for a fluctuating AC voltage
between affected subwoofer amplifier pin 8, circuit 172 (LB/RD) and
pin 7, circuit 169 (LG/BK).
for normal
operation.
Yes
GO to D9 .
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Yes
GO to D10 .
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Yes
GO to D12 .
No
GO to D11 .