Principles of Operation

Horn

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

The SJB (Smart Junction Box) supplies the control and switched voltage to the horn relay (integrated into the SJB (Smart Junction Box)). When the horn switch (part of the steering wheel) is pressed, ground is supplied through the clockspring to the horn relay. The horn relay is then energized, directing voltage to the horn and enabling the horn to sound.

The horn switch is comprised of 2 sets of contacts separated by springs. The lower set is connected to ground and the upper set is connected to the horn signal circuit. When the driver air bag module is pressed, it pushes down on the upper set of contacts, collapsing the springs, and allowing the contacts to touch. When the contacts touch it completes the circuit.

When the vehicle security system is armed, the SJB (Smart Junction Box) provides a momentary ground to the horn relay control side to indicate the system is armed and an on and off ground when an intrusion is detected or the panic alarm is activated.