why dose my car battary go dead
Asked by christinaandisrael Mar 16, 2013 at 10:10 AM about the 2005 Cadillac STS V8 AWD
Question type: Maintenance & Repair
8 Answers
could be a duff 1 or the alternator could be drawing charge back through a duff zenner diode
A diode by definition is a device that allows current to flow in one direction. A Zener diode is a diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage. Zener dfiodes are not used in automotive alternators. --- The battery could be losing voltage due to a parasitic drain. Here's a video explaining it and how to find it. https://www.youtube.com/watch?v=KF1gijj03_0
One of the most common things I see is one of the lights under the rear view mirror gets turned on when adjusting the mirror and this drains the battery.Check those first. Next disconnect the alternator wiring and check for an excessive drain.....do not confuse the small drain needed for "on star" and other computer related items.Generally a 12 volt test light put between the positive battery post and the positive battery cable with the cable disconnected from the battery should glow dim (normal)but not brightly. remove fuses one at a time until the test light glows dimly. (keep the doors closed and disconnect the under hood light if needed) Dim light OK Bright light DRAIN Disconnect the battery completely for a day or two,reconnect and see if it is still charged. Dead battery.......time for a replacement. Good battery......keep looking for a drain!
The Cadillac should have the battery saver function that will shut all circuits down after twenty minutes if a light was left on. It will not shut off the cigarette lighter circuits so don't leave anything plugged in with the engine off.
It could be an internal short in the battery. Try disconnecting the negative battery cable at night and see if the battery is flat in the morning.
migration_dmarrujo answered 9 years ago
My car will not start. I'm going to see if it's my battery. I use my car once to twice a week. I do leave my cigarette tray open all the time after disconnecting my phone charger.
My 07sts Cadillac keeping cutting off when I come to a stop
