Electrical Schematics

Wiring System:

The wiring schematic is the cornerstone of electrical diagnosis. Schematics break the entire electrical system down into individual circuits, showing the electrical current paths when a circuit is operating properly. Wiring which is not part of the circuit of interest is referenced to another page, where the circuit is shown complete. Schematics use a top (power) to bottom (ground) sequence to present electrical information.

IMPORTANT: It is important to realize that no attempt is made on the schematic to represent components and wiring as they physically appear on the vehicle. For example, a 4-foot length of wire is treated no differently in a schematic from one which is only a few inches long.

When diagnosing a horn problem, the technician would reference the horn section. The following schematic is a typical example of what would be found in a horn section, along with the included text.

Voltage is applied to the Horn Relay at all times. When the relay coil is grounded by closing the Horn Switch, the relay contacts close. When the relay contacts are closed, both the LH and RH Horns are energized.