During the production of VAZ-2108 cars, minor changes were made to their electrical equipment circuit, aimed at increasing the reliability of various systems and units. Thus, a starter relay, an ignition relay (see figure 106), glove compartment lighting lamp. The circuit for switching on the fog light in the rear lights has been changed (see chapter "Lighting and light signaling system"), added illumination of the outdoor lighting switch key. Some minor changes to the scheme are possible in the future.
A single-wire circuit for connecting electrical equipment devices is used in cars (figure 91). Consumers are connected to the "plus" of power sources by a wire, and to the "minus" - through the car body or "ground". This method allows to reduce the number of wires and simplify their installation. Connecting the "minus" of power sources to the ground reduces the wear of metal parts of the body due to electrochemical corrosion.
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Figure 91. Electrical equipment diagram of VAZ-2108 and VAZ-2109 cars:
1 - headlight; 2 - headlight washer motor*; 3 - underhood lamp switch; 4 - sound signal; 5 - Electric motor of the engine cooling system fan; 6 - electric fan switch sensor; 7 - Reverse light switch; 8 - wire tip for connection to brake pad wear sensor*; 9 - temperature indicator sensor; 10 - battery; 11 starter; 12 sensor-ignition distributor; 13 - spark plugs; 14 - generator; 15 - electromagnetic valve for switching on headlight washer*; 16 - ignition coil; 17 - Top dead center sensor; 18 - carburetor electromagnetic valve; 19 - carburetor limit switch; 20 - Oil pressure warning light sensor; 21 - Washer motor; 22 - electromagnetic valve for turning on the windshield washer; 23 - electromagnetic valve for turning on the rear window washer*; 24 - Switch; 25 - brake fluid level sensor; 26 - diagnostic socket; 27 - carburetor electromagnetic valve control unit; 28 - Windscreen wiper motor; 29 - socket for portable lamp; 30 - underhood lamp; 31 - mounting block; 32 - brake light switch; 33 - Carburetor air damper indicator lamp switch; 34 - heater lever illumination panel; 35 - cigarette lighter; 36 - Glove compartment lighting lamp; 37 - heater electric motor; 38 - additional resistor of the heater electric motor; 39 - heater motor switch; 40 - Instrument lighting switch; 41 - direction indicator, headlight and parking light switch; 42 - Sound signal switch; 43 - Windscreen wiper and wash switch; 44 - ignition switch; 45 - Outdoor lighting switch; 46 - Hazard warning switch; 47 - Fog light switch; 48 - Rear window heating switch; 49 - side direction indicator; 50 - Parking brake system indicator lamp switch; 51 - Ceiling light switch in the front door pillar; 52 - Ceiling light switch in rear door pillar**; 53 - instrument cluster; 54 - lampshade; 55 - rear light; 56 - Fuel level and reserve indicator sensor; 57 - rear window heating element; 58 - Number plate lights; 59 - Rear window wiper*; B - plug connector for connection to the individual interior lighting lamp.
* Installed on vehicle parts.
** Installed on VAZ-2109 and VAZ-21093 vehicles.
1 - headlight; 2 - headlight washer motor*; 3 - underhood lamp switch; 4 - sound signal; 5 - Electric motor of the engine cooling system fan; 6 - electric fan switch sensor; 7 - Reverse light switch; 8 - wire tip for connection to brake pad wear sensor*; 9 - temperature indicator sensor; 10 - battery; 11 starter; 12 sensor-ignition distributor; 13 - spark plugs; 14 - generator; 15 - electromagnetic valve for switching on headlight washer*; 16 - ignition coil; 17 - Top dead center sensor; 18 - carburetor electromagnetic valve; 19 - carburetor limit switch; 20 - Oil pressure warning light sensor; 21 - Washer motor; 22 - electromagnetic valve for turning on the windshield washer; 23 - electromagnetic valve for turning on the rear window washer*; 24 - Switch; 25 - brake fluid level sensor; 26 - diagnostic socket; 27 - carburetor electromagnetic valve control unit; 28 - Windscreen wiper motor; 29 - socket for portable lamp; 30 - underhood lamp; 31 - mounting block; 32 - brake light switch; 33 - Carburetor air damper indicator lamp switch; 34 - heater lever illumination panel; 35 - cigarette lighter; 36 - Glove compartment lighting lamp; 37 - heater electric motor; 38 - additional resistor of the heater electric motor; 39 - heater motor switch; 40 - Instrument lighting switch; 41 - direction indicator, headlight and parking light switch; 42 - Sound signal switch; 43 - Windscreen wiper and wash switch; 44 - ignition switch; 45 - Outdoor lighting switch; 46 - Hazard warning switch; 47 - Fog light switch; 48 - Rear window heating switch; 49 - side direction indicator; 50 - Parking brake system indicator lamp switch; 51 - Ceiling light switch in the front door pillar; 52 - Ceiling light switch in rear door pillar**; 53 - instrument cluster; 54 - lampshade; 55 - rear light; 56 - Fuel level and reserve indicator sensor; 57 - rear window heating element; 58 - Number plate lights; 59 - Rear window wiper*; B - plug connector for connection to the individual interior lighting lamp.
* Installed on vehicle parts.
** Installed on VAZ-2109 and VAZ-21093 vehicles.
In all the diagrams provided in the "Electrical Equipment" section, the color of the wires is indicated by letters, with the first letter being the color of the wire itself, and the second being the color of the stripe on the wiring (if it exists). Basically, the first letter of the color name is taken: B - white, G - blue, Zh - yellow, Z - green, K - brown, O - orange, R - pink, S - gray, F - violet, Ch - black. The exception is the color red, which is assigned the letter P (purple).
To facilitate installation, all wires are combined into bundles, and most of the bundles are made flat. In these bundles, the wires are welded to a tape made of polyvinyl chloride plastic. Flat bundles are easier to install on a car, especially under body trim parts. In addition, flat bundles provide better conditions for cooling the wires, and therefore it is possible to use wires with a smaller cross-section of the conductive core. As a result, copper and plastic used for insulation are saved.
Small-sized flat plug-in tips with an internal plug width of 2.8 mm are used to connect the wires. The plug-in blocks protect the connections well from water and dirt, which contributes to the reliable operation of electrical systems, especially the ignition system.
The connecting node of all the vehicle's electrical wiring is the mounting block (figure 92), located in the air intake box on the left side of the car. Through it, the front wire harnesses are connected to the instrument panel wire harness and to the rear harness. The colors of the wires connected to the connectors of the mounting block and the conventional numbering of the connectors in the sockets are given in Figures 93 and 94. For ease of maintenance, all fuses and auxiliary relays are placed in the mounting block, including the headlights, windshield wipers and washers, rear window heating, etc.
Figure 92. Mounting block (the lid is off):
1 - headlight washer relay (K6); 2 - rear window washer time relay (K1); 3 - relay-interrupter of direction indicators and hazard warning lights (K2); 4 - windscreen wiper relay (K3); 5 - contact jumpers in place of the lamp health control relay; 6 - rear window heating relay (K10); 7 - spare fuse; 8 - high beam headlight relay (K5); 9 - low beam headlight relay (KP); 10 - fuse; 11 - relay for switching on the electric motor of the engine cooling system fan (K9); 12 - sound signal relay (K8).
Figure 93. Colors of wires connected to the mounting block in the underhood space (the numbers are stamped with conventional numbers of the plugs):
W5 and W6-pads connecting to the front wiring harness; W7 and W8-pads connecting to the wiring harness of the left mudguard; Sh11-a block that connects to the wiring harness of the air intake box.
Figure 94. Colors of wires connected to the mounting block in the vehicle interior (the numbers indicate the conventional numbers of the plugs):
Sh9-block connecting to the rear wiring harness; W1—W4-pads that connect to the instrument panel wiring harness.
Electrical connections inside the mounting block (figure 95) are made on two double-sided printed circuit boards, connected by soldering into a single block. All output plugs of the mounting block are riveted to the printed circuit boards. To prevent accidental burnout of the conductive tracks of the printed circuit boards, it is not allowed to short-circuit the wires to ground when checking the serviceability of the electrical equipment circuit.
Figure 95. Wiring diagram of the mounting block (the outer number in the wire tip designation is the block number, and the inner number is the conventional plug number):
K1 - rear window washer time relay; K2 - relay-interrupter of direction indicators and hazard warning lights; K3 - windshield wiper relay: K4 - lamp health control relay (inside are shown contact jumpers that are installed instead of the relay); K5 - high beam headlight relay; K6 - headlight washer relay; K7 - window lifter power relay (not installed on VAZ-2108 and VAZ-2109); K8 - sound signal relay; K9 - relay for switching on the electric motor of the cooling system fan; K10 - rear window heating relay; K11 - low beam headlight relay.
The mounting block is covered with a transparent plastic cover on top, on which a conventional sign (symbol) is applied opposite each fuse and relay, showing which units of electrical equipment are protected by a given fuse or which relay is switched on. In total, 16 fuses are located in the mounting block. 13 of them are designed for a maximum current of 8 A, and three are designed for 16 A. These fuses protect most of the power supply circuits of the vehicle's electrical equipment (see table 3). The windshield wiper, headlight and rear window motor reducers also have additional thermal bimetallic fuses to protect against overloads.
The engine ignition system is not protected by a fuse, so as not to introduce an extra element into it that would reduce the reliability of the system in operation. The engine start circuit is also not protected, so as not to reduce the reliability of the start. In addition, the battery charging circuit, the carburetor electromagnetic valve control circuit, and the low and high beam headlight relay are not protected by fuses.
The power supply voltage to most consumers is supplied via the ignition switch. The power supply circuits of those electrical equipment units whose operation may be required under any circumstances are always connected to the battery (regardless of the position of the key in the ignition switch). These units include: a horn, brake light bulbs in the rear lights, a cigarette lighter, a lamp in the interior, a socket for a portable lamp and a power supply circuit for the hazard warning lights.