Test A: The Horn Is Inoperative

PINPOINT TEST A: THE HORN IS INOPERATIVE

A1-A4:

A5-A8:

A8-A10:

A10-A12:

A13-A14:

Normal Operation
When the horn switch is pressed, the instrument cluster receives a ground through signal circuit 10-GJ9 (GY/OG), the clockspring and ground circuit 31-GJ9 (BK/GN). The horn relay control and switched B+ power circuits are supplied by auxiliary junction box fuse 4 (15A) through circuit 30-GJ7 (RD/BU). The horn relay ground is controlled by the front electronic module (FEM) through circuit 91S-GJ7 (BN/RD). When the horn switch is pressed, the instrument cluster sends the FEM a command signal over the communication network to ground the horn relay. The FEM supplies a ground, energizing the horn relay and supplying power to the horn through circuit 30S-GJ6 (RD/YE). The horn is grounded through circuit 31-GJ6 (BK).

Possible Causes
- circuit 10-GJ9 (GY/OG) open
- circuit 30-GJ7A (RD/BU) open, or short to ground
- circuit 30-GJ7Z (RD/BU) open, or short to ground
- circuit 30S-GJ6 (RD/YE) open, or short to ground
- circuit 31-GJ6 (BK) open
- circuit 31-GJ9 (BK/GN) open
- circuit 91S-GJ7 (BN/RD) open
- clockspring
- horn relay
- horn
- horn switches
- FEM
- instrument cluster