Attention. If you are repairing any vehicle systems, especially electrical equipment, do not forget to disconnect the battery ground wire before starting work.
When replacing blown fuses, do not replace them with fuses of a different type or with other devices that replace normal fuses.
General description of the vehicle's electrical equipment
The main components of a 12-volt electrical system with a grounded "minus" are a 12-volt battery, a generator (crankshaft pulley driven) and starter.
The battery supplies current to the ignition system, lighting devices and other electrical consumers and has a reserve capacity in case the consumed current exceeds the current coming from the generator.
The generator has its own regulator, which provides high output power if the battery is weakly charged and the current consumption is high, and low output power if the battery is fully charged and the current consumption is low.
When connecting electrical components to the vehicle's on-board network with a grounded "minus", it is very important to connect them correctly if they contain silicon diodes or transistors, since if connected incorrectly, these components may fail. This applies to radios, tape recorders, electronic ignition systems, electronic tachometers, electronic corrosion protection devices, etc. - all of them must be connected in the correct polarity.
It is important to know that the positive battery cable must always be disconnected if the battery is being charged in the vehicle. If welding work is carried out using electric welding, the generator must also be switched off to avoid serious damage. Always check that the battery terminals are properly connected to the appropriate wires. When working with electrical equipment, it is recommended to disconnect the negative cable from the battery.
General recommendations for troubleshooting electrical equipment
Electrical faults are divided into three types:
- An electrical consumer that is not working is not supplied with current.
- The consumer himself does not work.
- The consumer is poorly grounded.
The first category of faults are the most complex. This is the power supply system that contains all the switches, relays, fuses, etc.
The electrical circuit can be checked with a test light with detachable wires on the other end that have alligator clips on them.
If the lamp does not work, follow a systematic approach to determine which of three causes is at play:
- Turn on the switch that connects the non-working lamp.
- Disconnect the power supply wire from the lamp.
- Connect the test light's ground wire to a good metal ground.
- Touch the test lead of the test lamp to the end of the power supply wire that was disconnected from the lamp. If current is supplied to the lamp, the control lamp will light.
Caution: If the lamp only comes on when the ground is turned on, make sure the ignition key is turned to the "on" position.
If the indicator lamp does not light, then there is a fault in the circuit between the battery and the lamp. As noted above, this includes all switches, fuses, relays, etc. Find this lamp on the electrical diagram and trace how the voltage goes to it. The fault is a break in the circuit between the battery and the lamp. If a fuse has blown and when replaced it immediately blows again, this means there is a short circuit in the circuit that must be found and eliminated. If the system has a switch, bypass it (short-circuit it to the "on" position) using an auxiliary wire, connecting it to the wire coming out of the switch. If the control lamp lights up, the switch is faulty.
Caution: Never replace the auxiliary wire with a light bulb, as it requires current from the battery.
Original text on the website: LADAman
If the control lamp does not light, then current is supplied to the lamp, i.e. the first of the possible causes is excluded. Connect the power supply wire and connect the auxiliary wire from the ground on the car body to the ground on the lamp. In this case, the switch connecting the lamp must be in the "on" position and the ignition must be on. If the lamp being tested only works when the ignition is on, this indicates poor grounding. This is usually caused by the metal surface on which the lamp is mounted becoming coated with a layer of foreign origin (paint, rust, etc.).
If none of the tests yielded any results, then the lamp itself is faulty. The above procedure can be used for any electrical consumer in the circuit by replacing that non-working consumer with a light bulb. Remember that for reliable operation of the electrical circuit, the connection points must be clean and tight.