Ford Fusion: Horn / Horn - System Operation and Component Description. Description and Operation
System Operation
System Diagram

| Item |
Description |
| 1 |
BJB |
| 2 |
Horn Relay |
| 3 |
Horn Switch |
| 4 |
Clockspring |
| 5 |
SCCM |
| 6 |
BCM |
| 7 |
Horn |
Horn Operation
The
horn switch consists 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 airbag 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 and
provides the ground signal, which is routed through the clockspring to
the SCCM and BCM. The BCM grounds the horn relay coil to energize the integrated relay in the BJB. When energized, the horn relay provides voltage to the horn, enabling the horn to sound.
DTC Chart
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices. REFER to: Diagnostic Methods (100-00 General Information, Description and Operation)...
Other information:
System Operation
System Diagram
Item
Description
1
BCM
2
Turn Signals
3
Horn
4
Door Ajar Switches
5
Hood Ajar Switch
6
Luggage Compartment Lid Ajar Switch
7
Right Door Lock Control Switch
8
IPC
9
Courtesy Lamps
10
Passive Key
11
RTM
12
Ignition Switch
13
DDM
14
GWM
15
GWM
16
PDM
..
Overview
The RCM continually receives and monitors inputs from the OCSM, BECMB and various other hard-wired switches and sensors. If the RCM
detects a sudden vehicle deceleration and/or lateral deceleration based
on the information received from the various sensors, and determines
that deployment is necessary, the RCM applies voltage and current to deploy the appropriate SRS components.
The S..