One thing all electrical parts have in common is a higher warranty return rate compared to mechanical parts. The reason for this is two-fold: electrical parts are more complex, so there's a greater chance the part may not work correctly when installed. But more often than not, the main reason why a brand new or remanufactured starter, alternator or ignition coil may be defective is due to misdiagnosis or mis-installation.

A high percentage of electrical parts that are returned by technicians because they were thought to be defective turn out to have nothing wrong with them. The reason the parts didn't work right or solve the customer's problem is because the vehicle was improperly diagnosed. Troubleshooting starting, charging and ignition problems isn't easy and often requires a number of tests to isolate the fault. Sometimes hurried technicians don't want to take the time to do all of these tests (or they don't know how!), so they jump to conclusions and replace the part that seems most likely responsible for the problem. Sometimes the technician is right, and sometimes he's not.

Problem 1:
The engine won't crank when the driver attempts to start the car. The technician tries jumping the battery, but the engine still won't crank. He concludes that the starter is bad and replaces it with a new one. However, the engine still won't crank. Obviously, it's not...