The usual electric chain consists of an electric element, switches, the relay, engines, safety locks, automatic switches, wires and sockets which connect an electric element to the rechargeable battery and a body. For the help by search of sources of malfunction of system of electric equipment in the management
schemes of electric equipment
of the car are provided.
Before trying to define a malfunction source, study the corresponding scheme of electric equipment for receiving idea of elements in this chain. The number of possible sources of malfunction can be reduced if to check work of other elements entering this chain. If several elements or chains fail at the same time, perhaps, the safety lock, the general for these chains or elements is faulty, or connection with a body - "weight" is broken.
The weakened or oxidized sockets, violation of contact with a body, the fused safety locks or faulty relays are causes of defect. Visually check a condition of all safety locks, wires and sockets in the failed chain before to start check of other elements. Use
schemes of electric equipment
for definition of places of possible malfunctions which need to be checked for detection of a source of malfunction.
The main devices necessary for detection of a source of malfunction, the tester or the voltmeter, a control lamp on 12 in, an ohmmeter, the battery and a set of wires with probes, a cap puncture are, it is desirable with the automatic switch or a safety lock which is used for a round of the checked wires or elements.
Except bad connection of wires in system of electric equipment two more main types of malfunctions — the opened chain or short circuit are possible.
The chain is disconnected as a result of break in electric equipment chain that interrupts current, causing shutdown of an element of electric equipment.
For check of an integrity of a chain connect the device for verification of schemes or the voltmeter: one conclusion to the negative plug of the rechargeable battery or the grounded element, another — to contact in the checked chain, it is desirable for the next to the rechargeable battery or a safety lock. At the same time the checked site of a chain has to be energized from the rechargeable battery, except for a case when the socket of connection to the battery does not carry current or the safety lock fused (do not forget that some chains of electric equipment join only at turn of a key in the ignition lock in a certain situation).
Include a chain, then connect the tester probe to connection, the next to the chain switch on the party of the checked element.
If there is tension (what fire of a control lamp or the indication of the voltmeter testifies to), so in the site of a chain between the corresponding connection and the switch there are no gaps.
If the site on which there is no tension is found, so the break of a chain happened between this point and a point of the previous check on which there was tension. The break of a chain is caused by the damaged or weakened socket.
The following consumers of the electric power can be possible sources of short circuit: lamps, electric motors, heating elements, etc.
Remove the corresponding safety lock and connect conclusions of a tester or the voltmeter to safety lock plugs.
Include food in chains, at the same time do not forget that some chains of electric equipment join only at turn of a key in the ignition lock in a certain situation.
If in a chain there is tension, so in a chain there was a short circuit.
The negative plug of the rechargeable battery is connected to "weight" — a body, the engine or the transmission. The unreliable or oxidized fastening can lead to refusal of an element or violation of its work. Do not forget that on many cars "mass" wires between some elements, such as the engine, transmission with a body are used, that is in those places where there is no direct contact between metal elements because of soft rubber fastenings or a paint coat.
For check of reliability of grounding of an element switch-off the rechargeable battery and connect one of ohmmeter conclusions to reliably grounded element. Connect other conclusion to a wire or connection with a body which needs to be checked. Resistance shown by an ohmmeter has to be equal to zero if is not present, then check connection as follows: if reliability of contact with "weight" raises doubts, then investigate connection, remove pollution and smooth out contacts. At assembly tighten fastening of the socket, having put a layer of technical vaseline or silicone lubricant for prevention of corrosion.