Check the battery
* Make sure the battery terminals are clean and tight.
*Measure the battery voltage using a voltmeter; should be at least 12.6 volts when off.
* Start the machine and measure the voltage again; must be at least 13.5 volts.
Check fuses and relays
* Locate the fuse box in the car. It is usually located under the hood or in the cabin.
* Examine the fuses and look for blown ones (those with a broken wire).
* Replace blown fuses with fuses of the same amperage.
* Check the relay for corrosion or damaged contacts.
Check wiring
* Visually inspect wiring for damage or corrosion.
* Check connections in the wire for loose or poor insulation.
* Use a test probe to check for power to various electronic components.
Check the generator
* The generator produces electricity to operate the vehicle’s electrical system.
* Check the alternator voltage as described in the “Check the Battery” section above.
* Check the alternator drive belt for wear or looseness.
Check the starter
* The starter starts the car engine.
* Check the connections on the starter for looseness or corrosion.
* Tap the starter with a hammer to release stuck contacts.
Check other components
* Ignition switch
* Electric door lock
* Engine computer
* Lights
Contact your mechanic
If you are unable to determine the problem yourself, contact a qualified mechanic. They can use specialized tools and experience to diagnose and fix your vehicle’s electrical problem.