Principles of Operation

Horn

Principles of Operation

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

The SJB supplies the switched and control voltage to the horn relay (part of the SJB). When the horn switch is pressed, ground is supplied to the horn relay coil through the clockspring. The horn relay then energizes, sending voltage to the horn, enabling the horn to sound.

The horn switch is comprised of the steering wheel and the air bag. They are separated by springs and both have 3 contacts. The steering wheel is the ground and the air bag has a single wire lead. When the driver air bag module is pressed, the springs collapse allowing the contacts to touch, completing the circuit.

The SJB also provides ground to the horn relay coil to sound the horn when the anti-theft system is armed, the panic button is pressed on the Remote Keyless Entry (RKE) transmitter, or to indicate a programming feature sequence.