Ford 2003 Mustang Workshop Manual page 3408

H2 CHECK POWER TO THE SUBWOOFER AMPLIFIERS
Key in OFF position.
Disconnect: LH Subwoofer Amplifier C4108a.
Disconnect: RH Subwoofer Amplifier C4109b.
Key in ON position.
Turn on the audio unit.
Measure the voltage between the subwoofer amplifiers pin 4, circuit
828 (VT/LB), harness side and ground; and between the subwoofer
amplifiers pin 5, circuit 828 (VT/LB), harness side and ground; and
between the subwoofer amplifiers pin 6, circuit 828 (VT/LB), harness
side and ground.
Are the voltages greater than 10 volts?
H3 CHECK GROUND TO THE SUBWOOFER AMPLIFIERS
Measure the resistance between the subwoofer amplifiers C4108a
(LH) or C4109a (RH) pin 1, circuit 694 (BK/LG), harness side and
ground; and between the subwoofer amplifiers C4108a (LH) or
C4109a (RH) pin 2, circuit 694 (BK/LG), harness side and ground;
and between the subwoofer amplifiers C4108a (LH) or C4109a (RH)
pin 3, circuit 694 (BK/LG), harness side and ground.
Are the resistances less than 5 ohms?
H4 CHECK THE SUBWOOFER AMPLIFIER ENABLE CIRCUIT FOR
POWER
Key in OFF position.
Disconnect: Subwoofer Amplifier C4109b.
Disconnect: Subwoofer Amplifier C4108b.
Key in ON position.
Turn the audio unit on.
Measure the voltage between the LH subwoofer amplifier C4108b pin
2, circuit 173 (DG/VT), harness side and ground; and between the
RH subwoofer amplifier C4109b pin 2, circuit 174 (GY/BK), harness
side and ground.
For Mach 1000
subwoofer
speakers,GO to
H10 .
Yes
GO to H3 .
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Yes
GO to H4 .
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Yes
GO to H5 .
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.