Test B: The Horn Is Always On

PINPOINT TEST B: THE HORN IS ALWAYS ON

Normal Operation
The horn relay is controlled through circuit 1 (DB) by the horn switch and through the lighting control module (LCM). When the horn switch is pressed, the horn relay control circuit 1 (DB) is grounded through the clockspring to the vehicle harness. The horn relay is then energized causing voltage to be applied to circuit 6 (YE/LG), enabling the horn to sound.

When the LCM has enabled the anti-theft system, the LCM supplies a ground through the horn relay control circuit 1 (DB). The horn relay is then energized causing voltage to be applied to circuit 6 (YE/LG), enabling the horn to sound.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Horn relay
- LCM
- Clockspring
- Horn switch (part of the driver air bag module and the steering wheel)
- Steering wheel switch harness

B1-B7: