The first thing that comes to mind is that you can't see the road map, you can't tell the fuses, you can't detect the failure points, and you often change the parts in a mess. In fact, car circuits are not as difficult as they would have been, and first, by grasping the underlying principles, we can take less turns。
First, you know the car circuit
Car circuits are essentially a question of “where electricity comes from, where it goes, who controls”. The cylinders provide electricity, the fuses are protected, switches and relays are controlled, and loads such as light bulbs, fanes, rain scrapers, etc. The easiest mistake for a newcomer is to stare at “any part that is broken” without thinking “if electricity is in place”。
Remember a central idea: check the power, check the controls, and finally check the load. This is the basic sequence of circuit screening and the first step in avoiding blind switching. Many of the seemingly complex failures are in fact power supply interruptions, poor access or iron-laying anomalies。
The circuits are not isolated parts but a set of links. You don't rush back models while you're studying, but you start by getting to know the concepts of "coherence, integration, insurance protection, iron return". Once the integrity of the circuit is understood, it will be easier to look at the road map later and check the failure。
Where did the power come from
Motor circuits are powered mainly by batteries and generators. When vehicles are out of fire, many basic functions are powered by batteries; when vehicles operate, generators start replenishing and charging bottles. The common area of error for newcomers is that the starter is suspected of having broken down as soon as there is no fire, but in practice, in many cases, it is just a bottle that loses power, a stake oxidizes, or the wire is loose。
Let's see if the voltage is enough, then the circuits are working. This is a practical way to judge the power supply chain. For example, if the light is not on, do not come up and remove the bulb, first confirm the bottle state, the fuse state, then check the plugs and the iron points. There was a problem with the power supply, and the behind elements would not work。
In daily exercise, the most likely to be overlooked are the poles and iron points. Both positive and negative voltage and oxidation can cause intermittent malfunctions, while iron failure can lead to dim lights, weak horns, and spasms. Many of these “faults” are actually the source of the problems of access。
Iii. Don't change fuses
The role of fuses is not to “strengthen the circuits”, but to burn themselves and protect the lines and equipment when the currents are abnormal. The most common mistake of the newcomers was to see the fuse burn and change it to a more specific one, which was felt to be “hard to break”. This is in fact very dangerous and could lead to heat on the circuits, burning wire beams and even greater damage。
The fuse burn is not the end point, but the point of failure. You have to think about why it burns: short circuits, damage to the internal parts, plugs into the water, grinding wires. If you change fuses and don't find a reason, the problem will be repeated。
You can judge it when you look at the look, then you can look back. For example, when a road fuse is set on fire repeatedly, the end of the road is checked to see if there is iron attached, if there is water corrosion, if there are metal components that break the insulation layer. The fuse will call the police, but it won't fix your failure。
Switches and relays
Many large current devices in cars are not directly controlled by buttons, but by relays. In short, the switch sends a “small signal” and relays are responsible for connecting to “large current”. If the newcomers do not understand this, and when the equipment is not working, it is easy to assume that the buttons are broken and that problems may actually be on relays, control lines or control signals。
To judge the failure of relays, do not just listen to "no sound." having a voice does not mean that the point of contact is certain or that the output is normal. The real idea is to see if there's a signal at the control end, if there's electricity at the output end and if the iron is normal. It's easy to misjudge an ear。
The learning focus for switches and relays is to understand the division of labour between “control” and “implementation”. Systems such as showers, air conditioners and heat fans are often indissociable from relays. With this layer of logic, you'll find that a lot of circuit failure isn't complicated, but that one of the chains of control is broken。
V. The iron is the easiest to forget
Iron is the current that goes back to the negative pole of the bottle, and it can't see, it can't touch, but it's crucial. Many newcomers look at the top, not the bottom, and the result is useless. In fact, iron-drying is one of the most common and easily underestimated problems in automobile circuits。
If the equipment is good or bad, the light is dark, and the instrument is abnormal, the iron is suspected. Flows of iron, rust and oil cover make the circuit incomplete. In particular, wet weather and older vehicles focus more on iron-linking。
Physical exercise is a habit of seeing electrical failure, first confirming whether the circuit is closed and then confirming whether the interface is secure. Don't run after the elements. You think they're broken, but they're not。
Vi. Relevant structure
The road map is not a back, but a logical one. New hands are the easiest to see because they look at the lines and the colours at first, but they don't see how the whole circuit works. The correct approach is to find the power source, then the control end, and finally the executive end, depending on the function。
When reading the map, look for "where to come from" and "where to go". So you can break a complicated drawing into a few little circuits. The figure is not more than who remembers it, but who can narrow it down faster。
It is recommended that the newcomer develop three habits: first, to identify the name of the element, then to look at the direction of the current, and finally at the connection. Once the logical sequence is fixed, the speed of the screening is significantly increased when there are electrical problems in the back, such as lights, electrics, sensors, etc。
Vii. Pocket of new hands
First, it's too fast. Many people replace their pieces as soon as they discover a malfunction, and the result is simply not a problem point. Secondly, basic checks are ignored. Power bottles, fuses, plugs and ironing are often the most vulnerable places. Third, based on experience. Circuit failure is the worst fear of feeling, and it must be checked one by one。
Do not interpret the word “restore” as “replacement”. The real circuit thinking is to determine which part of the malfunction occurred, not to bet on which parts are broken. As long as the method is right, many of the seemingly illuminating circuit problems become clear。
For those who have just entered the house, the most practical suggestion would be to write down four points of “power, control, load, iron” each time a malfunction occurs, and to follow the sequence. For a while, you'll find that you're getting more accurate and less able to spend your money。
The key to motor circuit learning lies not in the number of terms to be remembered at the outset, but in the right thinking: power first, control second, load later, and finally, don't forget iron. With this logic of looking at cars, checking lines, setting backs, the newcomers can slowly build up real physical capacity。
If you've just started the auto repair, it's suggested to start with the four basic points of bottle, fuse, relay, iron. What else do you want to know about road mechanics? Leave a message for the comment area. I can continue with your demolition。
