I've got all kinds of electrical troubleshooting tools both homemade and store bought, but here are some of my favorites:
The Fundamental Electrical Troubleshooting Shopbook - I keep recommending this one, but that's just because it's so damn good. It's electricity explained in a way like mechanics think, using terms that the average person can understand.
AES' Electronics Accupuncture Probes - The best backprobes on the market, bar none.
LOADpro Test Leads - Makes doing voltage drop testing by yourself easy and quick, without having to worry about finding a suitable load, how to backprobe molded connectors, etc. I use them pretty much daily, but they might be more useful for someone in an automotive or heavy equipment/truck shop than for a shadetree/homeowner.
Relay Test Jumper Kits both of them (and the
test lead kit that goes with them) - While they aren't a tool that sees everyday use, they are terribly handy for getting into circuits and testing operation under load. Sometimes they are the best way to see what's going on before resorting to tracking down hidden connectors or cutting open wiring harnesses.
Fuse Saver Kit (or the
Master Kit) - Which are great for tracking down pesky intermittent electrical demons that eat fuses. If you're cheap, a standard
5024 sealed beam headlight bulb along with some jumper wires can accomplish pretty much the same thing. (if it lights up you have a short, and the bulb limits current to the circuit to protect it)
A Fuse Socket Connector Set is handy for getting into fuseboxes, and *really handy* when paired with a standard ATC fuse holder and a low amp probe.
I've also got a handful of connectors clipped off of wiring harnesses with alligator plugs on the ends of the wires, for making testing easier on some of the more common components. Hit up a junkyard with a set of wire cutters, and grab the ones that look useful.
Retractable test leads in
different lengths are always handy, and keep your toolbox a little more organized. I've also got a couple sets of test leads that are homemade that have aviation style circuit breakers in them.
I've found that a lot of electrical troubleshooting isn't so much about the tools you have, but your ability to improvise as needed to troubleshoot problems. As an example, you can use a tool like a set of
noid lights for checking for electrical pulses that might be too quick for your meter. Don't limit yourself to thinking that a tool like a noid light is only useful for one type of job such as checking injectors. I've used them for all sorts of things over the years.
