The nominal voltage in the system is 12 V.
The electrical circuit diagram of the car is presented on figure 123.
In all the diagrams given in the chapter "Electrical equipment", the color of the wire is indicated by letters, where the first letter is the color of the wire itself and the second (if there is one) — color of the stripe on the wire: B — white; G - blue; Y - yellow; 3 - green; K - brown; P - red; O - orange; R - pink; C - gray B - black; F - purple.
Most circuits are turned on by the ignition switch. Always on (regardless of the position of the key in the ignition switch) power supply circuits for the horn, cigarette lighter brake light, interior light, portable lamp socket and the power supply circuit for the hazard warning lights.
(The text is copied from the online portal: www.vazbook.ru)
Most of the power supply circuits of the vehicle's electrical equipment are protected by fuses. The battery charging circuit, ignition and engine starting circuits, the carburetor electromagnetic valve control circuit, and the high and low beam headlight relays are not protected by fuses.
Before replacing a blown fuse, it is necessary to find out the reason for its combustion and eliminate it. It is not allowed to use fuses that are not provided for by the design of the car. When searching for a malfunction, it is recommended to review the table 16 circuits that this fuse protects.
When repairing a vehicle and its electrical system, it is essential to disconnect the wire from the negative terminal of the battery.
When checking the serviceability of the vehicle's electrical circuit, it is not allowed to short-circuit the wires to the body, as this may lead to burnout of the current-carrying tracks of the mounting block.
All fuses and auxiliary relays are located in a separate unit (mounting block), installed on the left side of the car in the air intake box for ventilation of the passenger compartment. In total, there are 16 fuses in the mounting block (13 for 8 A and three for 16 A - 4th, 8th and 12th) and there are sockets for installing 11 relays. However, not all relays are installed on the VAZ-2108 and not all fuses are used. These backup fuses and relays can be connected to other promising models of the Volga Automobile Plant, which will use the same mounting block.
The wiring from the engine compartment is connected to the wiring from the instrument panel and the vehicle interior via the mounting block.
The conditional numbers of the plugs in the connection blocks of the mounting block and the colors of the wires connected to them are indicated on figure 124 and 125. The internal connection diagram of the mounting block is shown in figure 126.
Repair of the mounting block mainly consists of replacing printed circuit boards. It is allowed to solder wires to replace burnt-out current-carrying tracks on printed circuit boards, but only if this does not require disconnecting the printed circuit boards.
To disassemble the mounting block, remove the cover and remove the relays, jumpers and fuses from the mounting block sockets. Then unscrew the fastening screws and remove the upper half of the mounting block housing and remove the printed circuit board block from the lower half of the housing.
The assembly of the mounting block is carried out in the reverse order of disassembly.