Ford 2003 Mustang Workshop Manual page 3403

PINPOINT TEST F: POOR QUALITY SOUND FROM ONE OR MORE
SPEAKERS (NOT ALL SPEAKERS)
F1 CHECK SOUND QUALITY
Key in ON position.
Turn on the audio unit.
Carry out the speaker walk-around test by pressing preset buttons 3
and 6 simultaneously.
Do all speakers have poor sound quality?
F2 CHECK CIRCUITS BETWEEN AFFECTED SPEAKER(S) AND
SUBWOOFER AMPLIFIERS
Disconnect: Subwoofer Amplifier C4108a.
Disconnect: Subwoofer Amplifier C4109b.
Disconnect: Affected Speaker(s).
Measure the resistance between the subwoofer amplifier and the
affected speaker(s) and between subwoofer amplifier and ground as
follows:
Speaker Circuits
Affected Speaker Pin Subwoofer Amplifier Pin
RF 1 (convertible only)
RF 2 (convertible only)
LF 1 (convertible only)
LF 2 (convertible only)
RR 1
RR 2
LR 1
LR 2
Are the resistances less than 5 ohms between the subwoofer
amplifier and the affected speaker(s) and greater than 10,000
No
GO to Pinpoint Test D
Test Step
LH 7
LH 8
LH 7
LH 8
RH 7
RH 8
RH 7
RH 8
.
Result / Action to
Yes
REMOVE the
audio unit and
SEND it to an
authorized Ford
audio system
repair facility.
TEST the system
for normal
operation.
No
For convertible,
GO to
For coupe, GO to
F4
For Mach 1000
subwoofer
speakers,GO to
F6
Yes
GO to
No
REPAIR the circuit
(s) in question.
TEST the system
for normal
operation.
Circuit
822 (BK/LG)
287 (BK/WH)
822 (BK/LG)
287 (BK/WH)
822 (BK/LG)
287 (BK/WH)
822 (BK/LG)
287 (BK/WH)
Take
F2 .
.
.
F3 .