Ford 2003 Mustang Workshop Manual page 3399

affected speaker(s) and between the subwoofer amplifier and ground
as follows:
Speaker Circuits
Affected Speaker Pin Subwoofer Amplifier Pin
RR 1
RR 2
LR 1
LR 2
Are the resistances less than 5 ohms between the subwoofer
amplifier and affected speaker(s) and greater than 10,000 ohms
between the subwoofer amplifier and ground?
D5 CHECK CIRCUITS BETWEEN THE AUDIO UNIT AND THE
SUBWOOFER AMPLIFIER
Disconnect: Audio Unit C290b.
Disconnect: Subwoofer Amplifier C4109b.
Measure the resistance between the subwoofer amplifier C4109b pin
5, circuit 169 (LG/BK), harness side and the audio unit C290a pin 6,
circuit 169 (LG/BK), harness side and between the subwoofer
amplifier C4109b pin 5, circuit 169 (LG/BK), harness side and
ground; and between the subwoofer amplifier C4109b pin 6, circuit
172 (LB/RD), harness side and the audio unit C290a pin 5, circuit
172 (LB/RD), harness side and between the subwoofer amplifier
C4109b pin 6, circuit 172 (LB/RD), harness side and ground.
Are the resistances less than 5 ohms between the subwoofer
amplifier and the audio unit and greater than 10,000 ohms
between the subwoofer amplifier and ground?
D6 CHECK SPEAKER(S)
Key in OFF position.
Substitute the affected speaker with a known good component.
Key in ON position.
Turn on the audio unit.
Is the affected speaker(s) operational?
D7 CHECK THE AUDIO UNIT
Key in OFF position.
Substitute the affected audio unit with a known good component.
Key in ON position.
Turn on the audio unit.
Is the affected speaker(s) operational?
Circuit
7 822 (BK/LG)
8 287 (BK/WH)
7 822 (BK/LG)
8 287 (BK/WH)
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Yes
GO to D6 .
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Yes
INSTALL a new
speaker. TEST the
system for normal
operation.
No
GO to D7 .
Yes
SEND the audio
unit to an
authorized Ford
audio system
repair facility.
TEST the system
for normal
operation.
No
REMOVE the
subwoofer
amplifier and
SEND it to an
authorized Ford
audio system
repair facility.
TEST the system