Mystery Problem..

[ak05 10+ year member]

Hello, i purchased a 2006 Chevy Cobalt LS. When i got the car i had an eclipse head unit put in, and a jensen 320w amp installed powering 2 12" woofers. Ever since i got the car, it randomly died. What happens EVERY TIME is i turn the key (to acc). Everything comes on normal, lights radio everything. But when i turn it again to start the car, everything shuts off. At this point the battery seems to be dead or near dead. If its dead the key is stuck in the ignition. If its near dead i can get the key out, but if i try to start the car again it just clicks and then completely kills the battery. Well i was not thinking it was the audio system, and eventually it stopped happening for a while. So i upgraded to a Hifonics 1600w Amp powering 2 Alpine Type-Rs. Well it started happening again. (It happened with the 320wamp, and it continues with the 1600w). Well after a couple trips to the dealership (without the amp in) they say theres nothing wrong with the car. So i keep putting the system in right when i get it back. Well i had the system out for a week and a half and it didn't happen once (usually averages about once a week). The next day i put the system back in (1600w amp) and it happened that day. I turned the key, everything came on, and i went to start the car and it just died. This happens even if the radio hasn't been on for days. But it only has ever happened when i had an amp hooked up to the battery.

What could the problem be? The battery and alt have both been tested and tested fine. The wiring as professionally done, and is correct. Does anyone have any idea what could be causing this? And what do i need to do to make it stop?

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[chuksw9ve 10+ year member]

I'm no expert,but it sounds like you have a short somewhere draining the battery.The sound system may make this happen faster.But like I said,I'm no expert,just trying to help.

 

[ak05 10+ year member]

anybody else..?

 

[thatsgonnahurt 10+ year member]

a couple of questions. how are you recharging the battery after its drained? do you do alot of "parking lot" listening (engine off)? do you have headlight dimming? what size is your alternator? is the battery drained sooner with the 1600w amp?

 

[helotaxi 5,000+ posts]

Do you knon that the amp is turning off when the car is off. It sounds like the amp is not shutting off when the car is off and that is draining the battery as the amp idles (about a 5A draw).

 

[ak05 10+ year member]

I never listen to the radio with the car off. And for your amp on with car off theory, on weekends the car sits in the garage for 2 days. And when i come back the battery is fine. I have a 105a Alternator. It does not happen sooner with the 1600w amp it happens exactly the same; when i turn the key. And the amp is not on when the car is off, i'd notice that, it has a HUGE neon blue light that comes on with the amp.

After it's drained we jump the car and let it sit, then drive for a day with the stereo off.

Do i possibly need a 2nd battery?

 

[helotaxi 5,000+ posts]

In that case it sounds like either you have a short in the car's wiring harness or the battery itself is bad and not holding a charge.

 

[ak05 10+ year member]

The battery has been tested. If there is a short how do i go about figuring out where it is, and how to fix it?

 

[coolahan 10+ year member]

If you bought it from a dealer take it back to them and ***** them out.

 

[ak05 10+ year member]

They already checked the car over several times. They say there is no problem.

 

[thatsgonnahurt 10+ year member]

time for a parasitic current draw test. which will determine the load on the battery when the engine is off. if you know how to use a dmm you can do this yourself otherwise take it to a mechanic.

 

[ak05 10+ year member]

13.4 with the car off. What should it read?

 

[thatsgonnahurt 10+ year member]

12.66 volts. the battery should be loaded when you measure voltage (engine off). turn on your headlights, radio to a modest level, acessories etc. then measure the voltage.

 

[ak05 10+ year member]

No problems there it reads what it should. Where do i go from here?

 

[Blazemaster83 10+ year member]

i would take it to the place that installed it, and show them the problem. they cant say nothing is wrong if it is tweakin out right in front of them....or take it to the dealership with the system in it, and show them...