when people start speaking "electrically" .... all i hear is Charlie Brown's school teacher.....
It's really simple. Electricity is just like water. If you think about it like plumbing, then it all makes sense. If there is a blockage in the pipe (broken wire, corrosion, etc) then the water (electricity) won't be getting to where it needs to go.
Checking for power to an item is pretty simple. You can buy a $5 test light that clips on to the negative terminal of the battery (or a clean metal part of the engine or body) and then use the probe to verify if you are getting power to where you want it. It won't tell you much more than that since you are only testing a small light bulb. If you are trying to power an item that requires a lot of electricity, then you might be getting enough power to light a test light, but not enough to make the item work. This happens with starter motors often because they require high amperage. I would recommend a multi-meter for diagnosing these things, although a test light will help immensely.
You can check the Ohms (resistance) of a wire by turning a multi-meter to the one that looks like a horseshoe- the omega. If the wire reads really really close to 0, then it has no resistance. If it reads anything higher, then it has resistance and electricity won't flow through it (think like an old iron pipe that has corroded itself closed on the inside). This test is good to see if you have a good ground between something like a fuel pump and the negative terminal on the battery. Since the metal body of the vehicle conducts electricity by design, you have to verify that it has good connections. You can also check resistance in any wire to verify that your + wire doesn't have a cut or anything through it. If you keep blowing a fuse, then one of your wires might have worn through the insulation and has grounded out. You can check for this by checking the resistance to the body.
On my bug many years ago, I couldn't get it started after towing it to a new place I was living. I used the bug to pack stuff into and when I unloaded, I couldn't get it started. I tried and tried, but it never fired off. After tons of trying this, that and the other, I checked to see if I was getting 12volts to the coil. Nope! I checked the resistance from the wire at the fuse box all the way to where it plugged into the coil. It read 1.0
Somewhere in between I had a break in the wire. I started tracing it and found a kill switch that cut power to the coil for an anti-theft device or something. I flipped the switch and it started up! Point is, you can check for power first and then diagnose which part is failing.
That's my electrical advice for the day. KC is probably right though: fuel pump could be bad.
