15.3.1. Detection of a rupture of a chain

15.3.2. Detection of a source of short circuit

15.3.3. Detection of bad grounding

The electric chain consists of an electric element, switches, the relay, safety locks, automatic switches, wires and the sockets connecting an electric element to the storage battery and "weight". For the help by search of sources of malfunction of system of electric equipment at the end of the management schemes of electric equipment of the car are provided.

Before trying to define a malfunction source, attentively study the corresponding scheme of electric equipment to receive idea of the elements established in this chain. Often it is possible to define a cause of defect, having checked functioning of other elements entering into this chain. If some elements or chains fail at the same time, the problem, obviously, consists in malfunction of a safety lock, the general for these chains or elements, or contact to a body.

Malfunction of electric equipment is quite often caused by such simple reasons, as the weakened or rusted sockets, absence of contact to a body, the fused safety locks, the melted burned-through crossing point or the faulty relay. Surely carry out visual check of a condition of all safety locks, wires and sockets in the failed chain before starting check of other elements. Use electric equipment schemes for definition of what of trailer clips are necessary for checking for detection of a source of malfunction.

The main tools necessary for detection of a source of malfunction, the tester or the voltmeter (a bulb on 12 In and pair of wires with щупами on the ends also can be used for carrying out some checks) are; ohmmeter; the battery and a set equipped щупами wires; a cap puncture (it is desirable with the automatic switch or a safety lock which is used for round of checked wires or elements).

For detection of the reason of unreliable work any of elements (usually because of bad connection or pollution of contacts, or), it is possible to inspect the damaged isolation by simple stirring of wires. It is necessary to shake a wire by a hand to check, whether lets about itself know malfunction at wire movement. This elementary method it is possible to narrow a circle of search of possible sources of malfunction to a minimum.

Along with problems of bad connection of wires, in system of electric equipment there are two main types of malfunctions — disconnection of a chain or short circuit.

Problems with the opened chain appear as a result of break in an electric equipment chain that interrupts current course. The opened chain will entail shutdown of an element of electric equipment.

The second problem is caused by short circuit of a site of a chain that leads to leakage of a current of other chain, usually directly on a body. The most probable cause of short circuit — violation of isolation of wires. Short circuit usually leads to a peregoraniye of the corresponding safety lock.