Horn System: Overview Ford Escape II

Principles of Operation

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

The SJB supplies the control voltage to the horn relay (part of the SJB). When the horn switch (part of the steering wheel) is pressed, ground is supplied to the horn relay sending voltage to the horn, enabling the horn to sound.

The SJB provides a momentary on then off ground when the panic button is pressed on the Integrated Keyhead Transmitter (IKT).

Normal Operation

The Smart Junction Box (SJB) supplies the voltage to the horn relay (part of the SJB). When the horn switch (part of the steering wheel) is pressed, the switch closes and ground is applied from the steering wheel switch harness through the clockspring to the horn relay through circuit CRH03 (BN). The horn relay is then energized, applying voltage to the horn through circuit SRH01 (YE/RD), enabling the horn to sound. Ground for the horn is supplied through circuit GD120 (BK/GN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Steering wheel switch harness
4. Horn
5. Clockspring
6. Horn switch (part of the steering wheel)
7. SJB

The Smart Junction Box (SJB) supplies the voltage to the horn relay (part of the SJB). When the horn switch (part of the steering wheel) is pressed, the switch closes and ground is applied from the steering wheel switch harness through the clockspring to the horn relay through circuit CRH03 (BN). The horn relay is then energized, applying voltage to the horn through circuit SRH01 (YE/RD), enabling the horn to sound.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Steering wheel switch harness
3. Clockspring
4. Horn switch (part of the steering wheel)
5. SJB