06 9-3 aero 2.8L battery draining

[Brian Swank]

I have a 2006 9-3 Aero 2.8 v6 and the battery will drain out dead to the point that I can't even unlock the ignition if the car is not driven every day. No lights or anything is being left on. Brand new battery didn't solve problem. Volt meter testing shows that alternator output is on point. Any ideas of what the problem might be? What to test next?

[toxicavenger]

So what is output of the alternator? It should be around 14volts.

Do you have a aftermarket alarm or radio installed?

[rpiereck]

Sounds silly, but check that random courtesy lights are going off when you close glove box, trunk, etc. I have seen a car that had a faulty glove box light switch, and with the bulb on all night the battery would drain.

[Hirsch]

Check the car also to see if the interior lights are on at random. A faulty ignition switch could be the problem.

There is a "plunger" that drops when you insert the key. If it goes bad, the plunger stays down making the car "think" that the key is in the ignition so the interior lights stay on until they time out. Then they come back on and time out again. It will repeat this cycle until the battery dies.

[Brian Swank]

Thanks for the replies! Alternator is putting out about 14 volts. stock radio and alarm (how i know if I'm screwed walking out to my car to go to work and the red light isn't blinking on the dash). I'll have to check the glove box and trunk lights as well as the plunger thing in the ignition.

Today I will be running a test with a 12 volt test light placed between the positive battery terminal and the positive lead. With the car turned off, the light will be on if something is using power such as the radio memory or alarm. Pull those fuses and if the light is still on you know another circuit is still using power. Pull fuses until the light goes off and you know what circuit the power is being drained from, then search that circuit for the problem.

[Brian Swank]

So its not the plunger, courtesy lights, alternator, bad battery. My fuse test was a lot more complicated than I had anticipated, mostly due to the MAXI fuses. the fuse section in the owners manual doesn't give enough information on what every single fuse is. Does anyone know of better fuse diagrams? something that shows what each circuit the MAXI fuses run? please leave me a link if you know!