Seems like using a voltmeter is common advice for a lot of the electrical problems we see. Got my HarborFreight advertisement in the newspaper today. Free multimeter with any purchase, or on the net, $3 for the same without other purchase.

http://www.harborfreight.com/7-funct...ter-90899.html

Weak amp meter, probably not practical at auto amperage, but usable voltmeter. These are also handy around the house if you need to do any wiring or see if a circuit is active.