Category: Automakers

Amateur Fitter

2023
Video: Amateur Fitter
Video: FULL CLUB FITTING WITH COBRA!! BLADES? 2023, February
Amateur Fitter
Amateur Fitter
Anonim

However, it’s not just the engine. The lights go out at night - you have to stand on the sidelines. The same thing awaits you in the rain when the wipers fail. It is extremely uncomfortable to drive a car with a failed heater, idle horn or heated rear window. There are many similar examples. Moreover, even in simple electrical equipment, it is sometimes difficult to locate and eliminate a defect - doing it on a real car is not at all like studying a circuit in a book.

Let me remind novice “fitter” that a lot of wires were saved in the car’s electrical equipment - the general “minus” for all systems is the body (“ground”, “ground”). And on the “positive” wires are supplied to numerous consumers. Of course, in real wiring there are still “minus” (usually they are short) wires - you cannot do without them. Because of what, then, the consumer may not work? (Of course, we mean good, otherwise there is nothing to look for here.) A frequent reason is the lack of a “plus”. He, for example, does not reach the fan motor, because the wire is broken. Or all the wires are in order, but the switch failed. However, newcomers have curiosities - they are looking for the missing “plus”, and the battery is dead. Or, God forbid, stolen.

But the “minus" for the consumer is vital. Most often, it disappears due to oxidation of the compounds of the wire with the body.

Quite often, especially on old cars that have been in the hands of garage "nuggets", the master discovers a "plus" where it should not be. After all, the do-it-yourselfer, having at hand wires, a soldering iron and electrical tape, can even turn the simplest wiring into a puzzle one.

A particularly dangerous malfunction is a short (that is, no load) short circuit of the "positive" wire to ground. If this section of the circuit is not protected by a fuse, then there is no harm. Well, if you just burn the wiring - but real fires happen.

A wire break is a classic circuit damage. The threat to its integrity arises not only at the joints of doors with struts, the hood with the body, etc., that is, near parts with large movements. If the wire is laid unsuccessfully, stretched, then eventually it will break from vibration, or the insulation will be wiped - then wait for the circuit.

[caption id = "attachment_188899" align = "aligncenter" caption = "Our probes:

homemade on the right.

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[/ caption] Other malfunctions are obvious even for a beginner: found - fixed, nothing to analyze. To identify others, you need at least a simple tool like a probe, which we often use in the workshop (photo 1). The little thing is tiny, inexpensive - and reliable. Let's practice!

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The device circuit is in fig. 1. Remember: the color of the glow - green or red - depends on the direction of the current. If the dipstick is on the “plus” and the clip is on the body, the glow is red. If the probe is also on the “minus”, the glow is green. If you want to make sure, take a look at photo 2. The lower fuse contacts are the “plus” of the battery. The light is red. And touch the probe clip - the light is green.

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In fig. 2 - a fragment of a typical automotive electrical circuit: Battery - fuse - circuit breaker - consumer. How to check this site with a probe? (The consumer is healthy.)

Let's start with the battery, as shown in photo 2. If there is a “plus” at point 1, you will have to check the circuit further. If there is no “plus”, then either the battery is discharged or it has an open circuit inside, or its “minus” terminal is disconnected from the body, or the wire between the battery and point 1 is broken. (If there was a short circuit in this section, the owner would know about it immediately The smell of burning insulation is unforgettable.)

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Is the battery ok? Check the fuse. Touch the probe of point 2. The light is red - the fuse is in order (photo 3). Green (photo 4)? So, between points 1 and 2, the circuit is interrupted - the fuse is blown or is out of order (for example, its contacts are oxidized) in the socket.

What do we have with the switch? If the probe glows red at point 3, the switch is closed. Green - open. Or … defective. Finally, we reached the consumer. The probe is at point 4. The light is red - the lamp is working, but the base has no connection with the “mass”. For example, a compound was oxidized (the scourge of automotive electrical engineering!). If the light is green, it means that the lamp is faulty (open circuit inside) - you can safely change it.

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In most cases, the failure of some consumer is best investigated, starting with a fuse. It is likely that it burned out. As you already understood, if the fuse is in order, then the glow of the probe at points 1 and 2 should be the same color. If it is energized, it means red. If the circuit is disconnected - green. But if at point 1 the light is red, and at point 2 it is green, then here is the place where the malfunction nests. You can check the fuse itself separately from the circuit - see photo 5. Green light - the fuse is alive. No glow - the circuit is broken. In the same way, they check the light bulb, the integrity of the winding of the gear motor, many relays, etc.

But why did the fuse blow? It is unlikely because of the standard load (if it corresponded to it, of course). Most often this is a consequence of a short circuit of the protected circuit. The "Kettle" will easily be convinced of this by hastily replacing the fuse - the new one will burn at the first click of the switch. But even in the simplest circuit, the circuit is sometimes not easy to find, and we are dealing with branched circuits when one fuse insures several consumers. First you need to at least sweep away known-good branches. Professional electricians, as well as experienced car enthusiasts, have long known the classic method of such a search. Let's make our probe in the form of a 12 V, 21 W lamp with two soldered wires and pins at the ends. (A lover of all that is thorough can equip a lamp holder with wires for inserting a lamp. This “device” can always be carried in a car, in which case a new bulb should be inserted briefly.)

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