Contents: Metal parts conduct ground current ↳ The wires and terminals are arranged… ↳ Common Wire and Terminal… ↳
Most Focus consumers have dual terminals. But often you can only trace one wire to the battery or alternator. The other terminates at some body ground, engine ground, gearbox ground, or other connector tab. To the uninitiated, the currents flow strangely.
Metal parts conduct ground current
Automotive manufacturers use a physical principle in on-board electrical equipment: metals - electricians call them mass - conduct current. Thanks to this, manufacturers save on wires - quite legitimately - to drain voltage to the negative pole of the battery: in a car, this work is done by the body. If the consumer does not work, then the reason is often not in the wire supplying the current, but in an incomplete connection with the mass. The contact with the mass then makes strange detours to the target. Consequence: the on-board electrical equipment becomes completely disordered. For example, you turn on the turn signal, and at the same time the taillight starts to blink in time with it. For an amateur, this seems strange.
The wires and terminals are arranged according to the system
Despite its rational design, the Focus's stretched wiring harness would stretch for about 10 km. Behind the seemingly chaotic jumble of multi-colored wires is a system - the colors of the wires indicate the path. In addition, most connections on multi-pin connectors and relays are numbered. Ford's standard uses common patterns when choosing wire colors.
Common Wire and Terminal Designations You Need to Know
Terminal 15: receives current only when the ignition is on from the ignition switch, and in addition to the ignition, current is also received by those consumers that should receive electricity only during the operation of the car. Numerous black wires in the Focus sometimes also have additional colored stripes.
Terminal 30: receives direct current from the positive terminal of the battery or from the generator when the engine is running. If the tools are handled carelessly, this can cause short circuits or cause a shower of sparks if the wire connected to the negative terminal of the battery is not removed. These wires, which are always under voltage, in most cases have a red sheath, sometimes with additional colored stripes.
Terminal 49: refers to the system of intermittent and emergency light signals.
Terminal 53: supplies power to the windshield wipers. The wires are predominantly green, with other additional colors (such as yellow) marked on them.
Terminal 56: from it, current is supplied to the low-beam headlights via yellow/black wires, and to the high-beam headlights via white/black wires.
Terminal 58: supplies power to the front parking lights, as well as to the rear lights and for the license plate light. The main color of the wire sheath is gray, sometimes with an additional color stripe.
Terminal 31: ground terminal, by means of which each consumer of electrical energy must be connected to ground. In the on-board network, the corresponding wires have a brown sheath.