Ford 2003 Mustang Workshop Manual page 3412

Speaker Circuits
Audio Unit C290a
Pin
2
8
Is the resistance less than 5 ohms between the audio unit and
subwoofer amplifier harness and greater that 10,000 ohms
between the subwoofer amplifier harness and ground?
H14 CHECK FOR AN AUDIO SIGNAL AT THE AFFECTED
SUBWOOFER
Key in OFF position.
Connect: Affected Subwoofer Amplifier.
Disconnect: Affected Subwoofer Speaker.
Key in ON position.
Turn on the audio unit and check for a fluctuating AC voltage
between affected subwoofer as follows: For right subwoofer pin 4,
circuit 187 (DB/OG) and pin 2, circuit 189 (LG/BK) harness side; and
between pin 3, circuit 179 (OR/RD) and pin 1, circuit 176 (PK/LG)
harness side. For left subwoofer pin 1, circuit 187 (DB/OR) and pin 3,
circuit 189 (LG/BK) harness side; and between pin 2, circuit 179
(OR/RD) and pin 4, circuit 176 (PK/LG) harness side.
Does the voltage vary as the volume is adjusted?
H15 CHECK FOR AN OPEN AND SHORT TO GROUND BETWEEN THE
AFFECTED SUBWOOFER AND ITS RESPECTIVE AMPLIFIERS
Key in OFF position.
Disconnect: Affected Subwoofer.
Disconnect: Respective Amplifier.
Measure the resistance between the affected subwoofer speaker and
its respective amplifiers, and between the affected subwoofer
speaker and ground as follows:
Speaker Circuits—Right Side
Affected Subwoofer
Speaker Pin
1
3
2
Subwoofer Amplifier Harness
Pin
8
7
Respective Amplifier
Pin
4
3
4
repair facility.
TEST the system
for normal
operation.
Circuit
No
172
REPAIR the circuit
(LB/RD)
(s) in question.
169
TEST the system
(LG/BK)
for normal
operation.
Yes
INSTALL a new
subwoofer
speaker.
No
GO to H15
Yes
INSTALL a new
subwoofer
amplifier.
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
Circuit
operation.
176
(PK/LG)
179
(OR/RD)
189
(TN/LB)
.