Test B: The Horn Is Always On

PINPOINT TEST B: THE HORN IS ALWAYS ON

B1-B2:

B2-B7:

B7-B9:

Normal Operation
The horn switch is grounded through the clockspring by circuit 31-GJ1 (BK/BU). The clockspring provides this ground signal to the instrument cluster through the horn switch on circuit 10-GJ9 (GY/OG). The horn relay control and switched voltage circuits are supplied by the auxiliary junction box (AJB) fuse 4 (20A) 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 pad 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 voltage to the horn through circuit 30S-GJ6 (RD/YE).

Possible Causes
- circuit 10-GJ9 (GY/OG) short to ground
- circuit 30S-GJ6 (RD/YE) short to voltage
- circuit 91S-GJ7 (BN/RD) short to ground
- clockspring
- horn relay
- horn switch
- FEM
- instrument cluster