If your vehicle needs a jump start to get going but then runs fine, the battery is most likely to blame. If it takes a jump but then dies after removing the jumper cables, you most likely have a bad alternator. Other common symptoms of a failing alternator include random dimming of dash lights, headlights, or other oddities of the electrical system. A high pitched squeal or screeching noise under the hood could mean your alternator diodes or bearings are going out. A failing alternator can ruin a good battery and a failing battery can wipe out a good alternator. Save yourself time, money, and grief… don’t ignore the warning signs!