Ford 2003 Mustang Workshop Manual page 3394

PINPOINT TEST A: THE AUDIO UNIT IS INOPERATIVE/DOES NOT
OPERATE CORRECTLY
A1 CHECK OPERATION OF THE AUDIO UNIT
Key in ON position.
Turn on the audio unit.
Is the audio unit display illuminated?
A2 CHECK FOR SOUND COMING FROM THE SPEAKERS
Verify that sound is coming from all the speakers.
Is there sound coming from all the speakers?
A3 CHECK THE AUDIO UNIT CONTROLS AND FEATURES
Refer to the owner literature for audio system controls.
Verify that the controls and features operate correctly.
Do the controls and features operate correctly?
A4 CHECK VOLTAGE AT THE AUDIO UNIT
Key in OFF position.
Disconnect: Audio Unit C290b.
Key in ON position.
Measure the voltage between the audio unit C290b pin 10, circuit
1002 (BK/PK), harness side and ground, and between the audio
unit C290b pin 9, circuit 828 (VT/LB), harness side and ground.
Are the voltages greater than 10 volts?
A5 CHECK THE GROUND CIRCUITS TO THE AUDIO UNIT
Key in OFF position.
Measure the resistance between the audio unit C290b pin 2, circuit
1205 (BK), harness side and ground; and between the audio unit
C290b pin 11, circuit 694 (BK/LG), harness side and ground; and
between the audio unit C290b pin 16, circuit 694 (BK/LG), harness
side and ground
Test Step
Result / Action to
Take
Yes
GO to A2 .
No
GO to A4 .
Yes
GO to A3 .
No
GO to Pinpoint Test
C .
Yes
System operation is
normal at this time.
No
REMOVE the audio
unit and SEND it to
an authorized Ford
audio system facility.
TEST the system for
normal operation.
Yes
GO to A5 .
No
REPAIR the circuit
(s) in question. TEST
the system for
normal operation.
Yes
REMOVE the audio
unit and SEND it to
an authorized Ford
audio system repair
facility. TEST the