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Yesterday, I spent 3 hours troubleshooting an issue where my car had no electrical power and couldn't start or crank. After carefully studying the car's circuit diagrams, removing panels and testing every suspicious component, including unnecessarily replacing a few worn looking components, everything tested fine. Frustrated, I was about to call a tow truck when my son suggested we investigate the battery and its connections.

I initially dismissed it because it's one of the first things I tested, but he insisted we test the terminal connections. I figured I would do it just to show him it's not the problem. I tested the wire from the battery to the main fuse and the voltage was was around 9V instead of 12.4V. I figured we should at least see some power instead of nothing at all. I thoroughly abraded and cleaned the terminals with baking soda and retested it again and got 12.4V. I asked my son to crank the car and Lo and behold it started!

It's hard to describe the feeling of joy and relief combined with embarrassment and a feeling of complete ineptitude. I realized I need to learn how to troubleshoot circuits instead of poking around aimlessly at components and replacing them. Are there any good training resources available, videos, book, articles, etc. I learn from?

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  • \$\begingroup\$ Product recommendations are off topic etc etc but checking that power is getting everywhere it's supposed to be is probably a good first step in every electrical troubleshooting journey. \$\endgroup\$
    – vir
    Jan 10 at 20:44
  • \$\begingroup\$ Apart from basic understanding of electronics, I'd say being systematic (start with the basics and move on in a single direction) is the key. With experience, more short cuts (making educated guesses) can be taken. \$\endgroup\$
    – Klas-Kenny
    Jan 10 at 20:47
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    \$\begingroup\$ @Klas-Kenny I hear you, but studying electronics the way it is presented using dry theory makes it hard to see how it applies to the real world. To give you an example, a bunch of recent MIT students were asked if they could light a small bulb using only a bulb, a piece of wire and a battery. Nearly all of them failed it. \$\endgroup\$
    – user148298
    Jan 10 at 20:53
  • \$\begingroup\$ @vir, I thought about that too, but I've encountered at least one question asking for an electronics book recommendation. Are learning and reference materials considered "products"? \$\endgroup\$
    – user148298
    Jan 10 at 20:56
  • \$\begingroup\$ FWIW, when it comes to car repairs, every shop manual has a 'monkey see monkey do' series of electronic tests that can be done by the mechanic. None of it requires any understanding of what they're testing. Believe me when I say, the average grease monkey does NOT understand how a modern car works - no way. I actually got in a minor argument with a mechanic couple years ago - He said dielectric grease on connectors improved their conductivity because the grease is conductive. IT IS NOT. Even after I took an ohmmeter to a glob of it, it wasn't enough to convince him so I dropped it. \$\endgroup\$
    – Kyle B
    Jan 10 at 21:05
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Not really an answer, but not enough room in 'comments' to post a long reply.

Please know I don't mean this to be flippant..... Troubleshooting electronic stuff well isn't something you can learn from reading a few articles. It's not like working with mechanics, where you can SEE what is happening (usually) and things work as per your intuition. (if the bolt breaks, use a bigger bolt etc.) In the world of electronics you have to KNOW what the right operation is, and have enough understanding to conjure explanations of why you're seeing whatever anomaly it is that you're seeing. This is only gained by experience and study. You have to really "learn electronics" and you have to build/test/teardown hundreds of actual circuits. There's a reason it takes 2 years to get an electronics tech degree and 4 years to get a bachelors.

I have yet to meet a mechanical engineer who actually understands electronics. Heck, I've known actual EE's who don't understand it very well.

Consider this... in 1820 we had steam powered ships crossing the Atlantic. But we were still detecting voltage using severed frog legs.

I'm not saying you can't do it of course! Lots of people can. But it's a result of years of experience. I just don't want you to be misled into thinking it's something you're gonna pickup in a weekend or two. And unfortunately there IS math involved :(

That said, if you're really wanting to get your feet wet this particular site is a pretty good place to start IMO. https://www.electronics-tutorials.ws/

And don't feel bad about the battery thing. I had the EXACT SAME EXPERIENCE (sorta) long ago. Car wouldn't start - no action when trying to turn the key. I replaced the starter motor, the starter solenoid, etc... When I checked the battery (before replacing anything), I found a solid 12V on it. After all the replacing, I went back and instead of probing the battery TERMINALS (the lead parts coming out of the battery), I probed the CLAMPS. Here I got ZERO VOLTS. In other words, even though it was a very tight mechanical connection, and it LOOKED good, there was no electrical conductivity between the terminal and the clamp! Pulled the clamp, cleaned it, and voila the car worked. (This was long before I started EE school FWIW)

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To become a proficient fault-finder on electronic circuits it is largely about studying, over a lengthy period of time, to learn about how individual electronic components perform and about how they can be interconnected to implement the many circuit building blocks typically utilised in practical circuits.

Fault-finding is then often about studying the circuit diagram of the circuit in question to figure out how the circuit is supposed to operate when it's functioning correctly and then making observations and taking measurements with, for example, an oscilloscope or multi-meter (volt meter).

Then it is a matter of trying to work out what could be causing the difference between how you understand the different circuit blocks should be functioning (with regard to the circuit diagram) compared to how they are actually functioning based upon your measurements and observations.

When fault-finding on a basic circuit, often much can be ascertained with just the aid of a volt meter.

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