why dose my car battary go dead


Asked by christinaandisrael Mar 16, 2013 at 10:10 AM about the 2005 Cadillac STS 4.6

Question type: Maintenance & Repair

10 Answers

John Sturman

could be a duff 1 or the alternator could be drawing charge back through a duff zenner diode

3 out of 3 people think this is helpful.

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

21 out of 21 people think this is helpful.

A lot of things can kill a battery. As I don't have the exact year of the car I'm going to take give you a few things to check. First of all have you battery tested to make sure it is up to the task of holding the parasitic loads this car has. if it checks good then here is a list of what to check next. Glove box light, make sure it turns off, if in doubt remove the lamp, trunk light same thing, underhood light also, interior lights and there is a lot of them, vanity mirror lights, stuck brake lights switch. If all of the lighting check out then you will have to check for excessive draw on the battery, like alternator diodes bad, stuck relays, alarm system. This can get involved. Good Luck

2 out of 2 people think this is helpful.

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!

6 out of 6 people think this is helpful.

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.

2 out of 2 people think this is helpful.

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.


How often do you drive the car? If it sits for extended periods of time the computers in the car will kill the battery. Disconnect the negative (-) battery cable if you plan on not using the car for more than about a week. HTH. -Jim

6 out of 6 people think this is helpful.

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.

1 out of 1 people think this is helpful.

Nope..its not my battery..

2 out of 2 people think this is helpful.

My 07sts Cadillac keeping cutting off when I come to a stop

Your Answer

Add photo

Related Questions

  • 1997 Cadillac gradually loses battery charge, along with some other minor issues that may be related. Any tips on how I might tackle this? 2 answers

    Hello everybody! A while ago, my 1997 Cadillac Seville started accumulating minor malfunctions before eventually becoming inoperable due to the battery being unable to keep its charge. It started off ...

    Cadillac STS


    Maintenance & Repair

  • 1996 STS, Goofy electric problems, can't make it up! HELP!!! 3 answers

    Car has a new battery, has had some weird things like the trunk or gas door opens on its own. In the past I would have trouble starting it, but I would pump the break, jingle a key turn it on wait fo...

    Cadillac STS


    Maintenance & Repair

  • Electrical Charging Problem 1 answer

    My 1997 Cadillac STS wouldn't start the other day. I took it in to a mechanic and had the old battery replaced with top quality, heavy duty battery. After ther car sat for a couple of days, the batt...

    Cadillac STS


    Maintenance & Repair

  • 2006 STS battery issues 1 answer

    My 2006 STS battery goes dead after a week. I had it jumped and tested by AAA and it seemed to work fine for about a month. I bought a battery saver trickle charger and it seemed to help for a few w...

    2006 Cadillac STS V6


    Maintenance & Repair

  • Why does our battery keep going dead? 5 answers

    we keep putting batteries in the car and within a week it is dead. We just put $500. into and it was good for 3 months and we out to start it the other day and it was dead. There has to be somethin...

    1999 Cadillac Eldorado Base Coupe


    Maintenance & Repair

Looking for a Used STS in your area?
CarGurus has 1,495 nationwide STS listings starting at $2,995.

Search Cadillac STS Questions

Cadillac STS Experts

#1 tenspeed
Reputation 260
#2 Js08016
Reputation 70
#2 tennisshoes
Reputation 70
View All

Related Models For Sale

Used Cadillac CTS"
339 Great Deals out of 14,063 listings starting at $1,800
Used Cadillac DTS"
101 Great Deals out of 1,930 listings starting at $2,650
Used Cadillac SRX"
402 Great Deals out of 17,613 listings starting at $2,950
Used Cadillac Seville"
519 listings starting at $2,500
Used Cadillac STS-V"
3 Great Deals out of 34 listings starting at $10,900
Used Cadillac CTS-V"
10 Great Deals out of 381 listings starting at $7,995
Used Cadillac Escalade"
234 Great Deals out of 8,136 listings starting at $3,477
Used Cadillac DeVille"
19 Great Deals out of 2,292 listings starting at $1,499
Used Chrysler 300"
472 Great Deals out of 22,370 listings starting at $2,500
Used Dodge Charger"
477 Great Deals out of 32,136 listings starting at $3,450
Used BMW 7 Series"
96 Great Deals out of 4,828 listings starting at $3,595
Used Chevrolet Impala"
1,612 Great Deals out of 45,449 listings starting at $170
Used Mercedes-Benz E-Class"
649 Great Deals out of 24,516 listings starting at $1,999

Used Cars For Sale

2011 Cadillac STS For Sale
8 Great Deals out of 139 listings starting at $11,999
2010 Cadillac STS For Sale
3 Great Deals out of 53 listings starting at $8,450
2009 Cadillac STS For Sale
138 listings starting at $9,990
2008 Cadillac STS For Sale
11 Great Deals out of 252 listings starting at $7,900
2007 Cadillac STS For Sale
11 Great Deals out of 238 listings starting at $3,800