Test A: The Navigation System Is Inoperative

PINPOINT TEST A: THE NAVIGATION SYSTEM IS INOPERATIVE

A1:

A1-A3:

A3-A5:

Normal Operation
The audio unit receives voltage on circuits 137 (YE/BK) and 956 (OG/LG) and is grounded by circuit 694 (BK/LG). A start signal is received through circuit 1786 (BN/PK).

Possible Causes
- fuse(s)
- circuit 137 (YE/BK) open
- circuit 694 (BK/LG) open
- circuit 956 (OG/LG) open
- circuit 1786 (BN/PK) short to voltage
- audio unit