Can anyone recommend a good book or two for someone who knows nothing about electrical systems to get started? Well maybe not "nothing", I know red is positive and black is negative and resistance is what employed anytime a problem with an electrical part came up. I need to move past the point of just being able to change a battery or plugging into an existing connection.
Start here, not a lot of basic theory, but a lot of good tips. http://madelectrical.com/electrical-tech.shtml
My advice is to stay away from school (high school, college) electrical books. They are all theory and very little practical application and testing. What you really want to know is how do I test and electrical system that isn't working? A couple of points: In order for an electrical system to function, it must have a completed path from power to ground. For an electric device to function properly it needs to be supplied design voltage and have a good ground path. With that in mind, you can easily test any electrical device with a digital volt, ohm meter (DVOM). The method I have taught for years is to start by connecting the negative lead of the DVOM to battery negative at the battery. If you are working inside the vehicle you will need an extension cord for the negative lead. Use the positive lead to test the battery voltage, it needs to be at least 12.4 volts. If it isn't, charge or replace the battery. Now, turn the broken device on and see that the battery voltage stays above 11.0 volts. The battery should also be able to recover to 12.4 volts when you turn the device off. (high current devices such as blower motors and headlamp circuits will drop the battery voltage when they are on)(the starter circuit will drop the battery voltage even more) Now find a test point as close as possible to the now working device. Use the positive DVOM lead to check the power supplied to the device (negative lead still connected to battery negative and the device circuit powered, turned on). The power side of the device should read within 0.2 of a volt of the battery voltage you just measured. Now move your positive lead to the ground side of the device. The DVOM should read no more than 0.1 volt. A reading of 0.0 volts on the DVOM would be perfect. If you read within 0.2 volts of battery voltage on the power side and no more than 0.1 volt on the ground side, the device is bad and must be replaced or repaired. If you read a voltage lower by more than 0.2 volts of battery voltage on the power side and no more than 0.1 volt on the ground side, you have excessive resistance on the power side of the circuit. It could be a switch, fuse, relay or a bad connection. (eg. battery voltage is 12.2 with the device on and you measure 10.2 on the power side) If you read within 0.2 volts of battery voltage on the power side and more than 0.1 volts on the ground side, you have excessive resistance in the ground circuit. In fact, if the ground side is open you will read battery voltage at this point. Now you are looking for a broken wire or a bad connection. You can narrow down the location of the excessive resistance by moving your test point in the circuit closer to the battery either the positive or negative post based on what the above tests told you. Once you get a reading in spec, the problem lies between the last bad reading and the first good one. A couple of points to remember: leave the DVOM negative connected to battery negative at the battery the circuit for the problem device must be turned on and live you must have a good battery that will hold a stable voltage to perform these tests. You can test the integrity of any circuit on the car with this test procedure. I did mention that the starting circuit is a bit different. That difference is that voltage will drop considerably once you engage the starter. As long a battery voltage stays above 9.6 volts with the starter energized, you can test it just like any other circuit. You just need to remember what your battery voltage is during cranking. Also the specs are a little higher, within 0.3 volts of battery voltage on the power side and no more than 0.2 volts on the ground.
If you go to youtube, there are a lot of videos on basic automotive electricity. I was looking for one in particular that did a really good job. The guy that put it up used a white board and it looked like that writing and diagrams wrote themselves while he explained what was going on. However, it doesn't seem to be available. If you want to see an excellent electrical troubleshooter at work, take a look at South Main Auto Repair on youtube. He does all types of repair videos. His electrical troubleshooting videos are very, very good.
There is (in a simple world) the; power source power switching device power consuming device and the conductors that connect them
I've found the below site to have a lot of info. Mostly towards the car audio side but it covers area's like relays, fuses, circuit breakers, wire, diodes, switches, charging systems, and so on. http://www.bcae1.com/ Jim
My advice to you is remember you are just working, on one circuit! It goes from the source (battery) through a wire to a switch of some sort, then the circuit continues to the appliance, then back to the source. This is a simplified example. If you try to look at a schematic all at once, it can be confusing! KISS! Bones
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