Test A: The Horn Is Inoperative

PINPOINT TEST A: THE HORN IS INOPERATIVE

A1-A4:

A5-A7:

A8-A10:

A10-A13:

A13-A14:

Normal Operation
The horn relay control voltage and the horn relay switched voltage circuits are supplied by the smart junction box (SJB) fuse 38 (15A). The horn relay is integral to the SJB. Voltage is supplied to the SJB horn relay fuse 38 (15A) from the battery junction box (BJB) through circuit 1052 (TN/BK). The horn relay is controlled by circuit 1 (DB) through the steering wheel horn switch. When the horn switch is pressed, the horn relay control circuit 1 (DB) is grounded through circuit 848 (DG/OG) to the speed control servo. The relay is then energized causing voltage to be applied to circuit 6 (YE/LG), enabling the horns to sound. Ground to the horns is supplied through circuit 57 (BK).

Possible Causes
- fuse
- circuit 1 (DB) open
- circuit 6 (YE/LG) open
- circuit 57 (BK) open
- circuit 848 (DG/OG) open
- circuit 1052 (TN/BK)
- horn
- horn switch
- clockspring
- speed control actuator
- SJB