A myriad of electrical gremlins can come to light with a car’s age—bad terminals, broken wires, blown fuses, and even fried relays. Knowing how to diagnose those problems can be the difference between ...

If you’ve never used a voltmeter to test electrical circuits on 12-volt farm equipment, cars or trucks, but wanted to learn, here’s how: Voltmeters cost from $15 to $300. $50 will buy an economy-grade ...