Operation CHARM: Car repair manuals for everyone.

Test B: The Horn Is Always On

PINPOINT TEST B: THE HORN IS ALWAYS ON


B1-B4:






B5:






Normal Operation
The horn relay (part of the smart junction box [SJB]) receives the switched and control voltage from the battery junction box (BJB). When the horn switch (part of the driver air bag module) is pressed, the switch closes, receiving ground from the vehicle harness through the clockspring. Ground is then supplied to the horn relay (part of the SJB) through circuit 1 (DB) energizing the horn relay. The horn relay sends voltage to the horn through circuit 6 (YE/LG), enabling the horn to sound.

Possible Causes
- Circuit 1 (DB) short to ground
- Circuit 6 (YE/LG) short to voltage
- Clockspring
- Horn switch (part of driver air bag module)
- SJB