General information
The electrical system of the engine mainly consists of charging and starting systems. Since these are engine-related functions, they are described separately from body electrical equipment such as lighting, instrumentation, etc. (which is described in chapter 12). Refer to Part B of this chapter for information on the ignition system on petrol models and Chapter 5B for information on the preheating/afterheating system on diesel models.
The electrical system has a supply voltage of 12 V, the negative terminals are connected to «weight».
Rechargeable or requires little maintenance («low maintenance»), or no maintenance at all («maintenance-free»), i.e. sealed for life. The battery is charged by the alternator, which is belt driven by the crankshaft.
A starter with a traction solenoid is used, designed to pre-engage the drive gear. When the engine is started, the electromagnet moves the drive gear and engages it with the flywheel ring gear, and this occurs before power is supplied to the starter. Immediately after starting the engine, while the gear has not yet disengaged from the flywheel, the overrunning clutch (freewheel) prevents forced rotation of the starter armature from the engine.
Precautionary measures
Additional details regarding the various systems are given in the relevant paragraphs of this chapter. While some repair procedures are given, the usual course of action is to replace the problematic item.
When working on the electrical system, you must be very careful to avoid damaging semiconductor devices (diodes and transistors) and the risk of injury. In addition to the precautions mentioned in paragraph «Safety first!» at the beginning of this manual, observe the following rules:
- Be sure to remove rings, watches, etc. before working on the electrical system. Even when the battery is disconnected, the capacitor may discharge if the live terminal of the cell is grounded through a metal object. This may cause electric shock or severe burns.
- Do not reverse the polarity of the battery terminals. Elements such as a generator, electronic control units or any other elements that have semiconductor circuits in their composition can be irreparably damaged.
- If the engine is started with wires «cigarette lighter» and an external battery, connect the batteries according to the scheme «plus with plus» And «minus with minus» (see «Starting the engine from a foreign battery» at the beginning of the guide). The same rule is true for connecting the charger.
- Never disconnect the wires from the battery terminals, alternator, any electrical wiring and electrical connectors or instrumentation while the engine is running.
- Do not allow the engine to crank the alternator when it is not connected to the vehicle's electrical system.
- Never «check» generator output by shorting the output wire to ground.
- Never use an ohmmeter with a built-in hand-operated generator to test electrical circuits.
- When working on the electrical system, be sure to disconnect the ground wire from the battery.
- Before using electric welding equipment on a vehicle, disconnect the battery, alternator, and components such as electronic control units for various vehicle systems to prevent damage.