Test A: The Audio Unit Is Inoperative/Does Not Operate Correctly

PINPOINT TEST A: THE AUDIO UNIT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY

A1-A4:

A4-A5:

A5 Continued:

Normal Operation
The audio unit receives power on circuit 137 (YE/BK) (hot in RUN/ACC) and circuit 956 (OG/LG) (hot at all times). The audio unit is grounded on circuit 694 (BK/LG). A redundant ground is added on circuit 57 (BK) for all but the Mach 300 audio systems. With the ignition switch in the RUN/ACC position, all of the features are operational.

Possible Causes
- circuit 137 (YE/BK) open
- circuit 956 (OG/LG) open
- circuit 694 (BK/LG) open
- circuit 57 (BK) open
- audio unit