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Detection of bad grounding

The negative battery terminal is connected to "weight" - the metal body of the engine or the gearbox; with many electrical components connected in such a way that it is suitable only for the positive wire, this current returns to the battery through the metal body. This means that the electrical mounting element and the body are part of the electrical circuit. As a result, bad or rusted fastening can cause refusal of work of an element or lead to its unstable or bad work. In particular, bulbs can burn dim light (especially if in a point of grounding of this bulb is carried out grounding of any else included element of an electric equipment), electric motors can slowly work, and the work of one chain can have an imperceptible at first sight on work of other chain.

Do not forget that on many cars grounding wires between some elements, such as the engine / transmission and body, that is, in those places where there is direct contact between metal elements because of soft rubber fastenings or a paint layer.

To check the reliability of grounding of an element it is necessary to disconnect the battery and connect one lead of an ohmmeter to reliably earthed element. Connect the other probe to the wire IPT connection with a body that should be checked. Shown by an ohmmeter resistance should be equal to zero; if not, check the connection as follows.

If you assume absence of grounding, disassemble connection and clear a site of a body and the wire plug (or the surface of the earth element) to pure metal. Carefully remove all traces of dirt, then use a knife remove all paint so that reliable contact of two metal surfaces. When assembling tighten the mounting socket; When connecting the plug of a wire establish a washer with the jagged edges between the plug and the surface of the body to ensure a reliable connection. When connecting prevent corrosion occurrence in the future, having put a layer of Vaseline or silicone grease.