Fig. 15.0. Location of contact connectors and wire harnesses in the car: a — contact connector; 1 – Engine cooling system fan wiring harness; 2 – Engine compartment wiring harness; 3 – air conditioner wiring harness; 4 – Engine management system wiring harness; 5 – ignition coil wiring harness; 6 – Headlight washer/wiring harness; 7 – radio wire harness; 8 – door to door wiring harness; 9 – mirror adjustment wiring harness; 10 – door wiring harness; 11 – Airbag wiring harness; 12 – Rear speaker wiring harness; 13 – trunk wiring harness; 14 – trunk lid wiring harness; 15 – Fuel tank wiring harness; 16 – Automatic transmission selector lever lighting wiring harness; 17 – Interior lighting wiring harness; 18 – Automatic sunroof wiring harness; 19 – main wiring harness; 20 – Windshield heater wiring harness; 21 – Central Joint Block (CJB); 22 – Air conditioning compressor switch wiring harness; 23 – Distribution Block (BJB); 24 – Reverse light switch wiring harness
Without a battery, the starter and generator installed on the car will not work, almost 10 km of wires will be left without electricity. If the battery is disconnected, the starter will not work, without a starter the engine will not start and the generator will not work, without wire harnesses these three most important units will not even be able to start working - they will be completely "isolated".
It is not surprising that many drivers associate unpleasant memories with three main elements - the battery, starter and generator. They are located in the engine compartment, where the operating conditions are far from ideal: sometimes too cold, sometimes too hot and very often humid. Many consumers of electricity are located in places exposed to atmospheric phenomena, which leads to a malfunction in the on-board network. In addition, the current generated by the battery decreases in severe frost.
After studying this section, you will be able to correctly determine why a switch does not work or a lamp does not light. Often the cause of the malfunction is an unreliable contact of the electrical connector or its corrosion. Many electrical equipment malfunctions can be eliminated with simple techniques.
TECHNICAL DICTIONARY
Basic concepts
Electrical circuits consist of sources of electrical energy (e.g., battery, generator), the end consumer of electrical energy (incandescent lamp, starter, electric motor) and wiring harnesses consisting of several individual wires. Wiring harnesses form the necessary connections between sources and consumers of electrical energy.
Voltage.
It's like the pressure of water in a water pipe; measured in volts (V).
Electric current.
Similar to the volume of water flowing in a given time. Current is measured in amperes (A).
Power.
The product of current and voltage determines the electrical work, measured in watts (W), produced by a current source to power an electrical consumer.
Resistance.
It is determined by dividing the voltage applied to a certain section of an electric circuit by the current passing through this circuit. It is measured in ohms (Ω). Resistance (resistor) can be imagined as a tap in a water pipe. When the tap is open, the resistance is 0 and the water flows freely. If the tap is closed, the resistance increases to infinity (Ґ) – the water flow stops.
Wire.
The main parameter of the wire is the cross-sectional area, which is selected in accordance with the power (current consumption) of a specific consumer of electrical energy. For a control lamp, a wire with a cross-sectional area of 0.5 mm² is sufficient, and for connecting the starter to the battery, a wire with a cross-sectional area of 16 mm² is used. If a thin wire is used in a circuit with high currents, it heats up, the voltage drop increases, as a result of which instead of the required 12 V, only 10 or 9.5 V will be supplied to the headlights, as a result of which the lamps will burn at half power.