I've got a tiny little $20 RadioShack one that I can throw around or take with me just in case.

But I like my Fluke 179... They both work, but it's like putting down your $3 department-store ratchet wrench & picking up a SnapOn.

Helm manual is pricey, but it's got a lot more detail than the $12 Chilton/Haynes/whatever...

The domelight problem isn't directly related, but it's a hint about what condition your wiring harness is in. Finding breaks & shorts is a PITA, but you're stuck with it unless you want to junk the car. You'll find the Helm book has pretty detailed troubleshooting stuff for any component. You don't have to really understand electricity; it'll tell you where to poke the leads of your meter.

You'll also want to get some other stuff like wire, alligator clips, & a handful of connectors. You might have to make up some jumper wires to do some of the tests.