adlong

Good Morning,

I was fiddling with my ipod integration cable and trying to get it to recognize my iphone 4, which it wont, and instead of turning my car on with the push button (which I do 99.9999%) of the time, I used the key to put it on ACC. Well, I left the key in that potion and went inside and never came back (birthday party was going on).

Next day the battery was dead. Assuming the aux. battery is also toast. I charged the main battery fully, but haven't touched the aux. battery or hooked the battery back up. Questions:

Do i need to also charge/replaced the Aux battery since it is also probably dead?

What else do i need to check/mess with/worry about prior to hooking the newly charged rear battery up?

Thank you in advance for your help!

Adam

adlong

Anyone? I would like to get the car back on the road tonight. Any help is greatly appreciated!

Plutoe

Once you get a good main battery connected and the car drivable---run the car at hwy speeds for an hour and the aux battery should take care of itself, that is if the charging and battery control system is correct!

adlong

What do you mean charging and battery control system being correct?

starbrite

He means if they are in good shape and can charge correctly.

adlong

Thanks for the replies folks. Fired her up and she works just fine. I re-synced the windows. Anybody have a chart identifying which fuse/boxes go to which things? I need to pull the sunroof/moon roof shade fuses to re-synch.

starbrite

My main battery went dead this weak when I accidentally left my hazard flashers on overnight. Voltage was all the way down to 3.5 Volts. I disconnected the ground and charged it back to full capacity. First with a 4 amp charger to about 75% and then the remaining with a Ctek charger

I checked the aux battery and it was fine @ 12.37 V, on a very cold day, 19 degrees F. So ,apparently when the car isn't running, the BCM takes the aux battery out of the circuit and just the main battery drains.

Now, to be able to get the darn filter cover back on completely.

Critter

Did not read the whole post but " I checked the aux battery and it was fine @ 12.37 V, on a very cold day, 19 degrees F " That my friend is a dead battery 12.6V is about 80% at best. Change out the aux battery!!

starbrite

What are you saying Critter, that my 11 yr old, original Fiamm, is giving up the ghost?
Say it isn't so!!

The car had been sitting for a week and half, so Ill check it again after driving it a bit. Or maybe just go ahead and charge it.

Critter

Yes that is what I am saying if this battery is 11 years old then change it out, the alternator and regulator as well as numerous other electronic power hungry devices will also give you better service.
Hopefully you are joking, 11 years, just who services this car.

starbrite

No, I'm not joking, this is the original oem battery in my '04.

Car serviced by local MB dealership.

Critter

First off, get a battery, then go to the dealership service manager and ask for all the money you spent on Checks, because they have not been doing them now have they.
11 year old battery, controlling hopefully not your braking system, does you car have SBC?? unsure of your model car.


Just curious how old is the main?

starbrite

Yes, the aux battery's main purpose is backup for the SBC braking system when alternator fails and main battery becomes discharged. Keep in mind that I'm not getting any kind of battery warning msg in the instrument cluster, which happens when the aux battery is failing.

Main battery was replaced about 4 yrs ago with a Deka AGM.

Speaking of checks, New York safety inspection requires checking the aim of the headlight's low beams . A couple of weeks ago I discovered that my drivers side headlight was aimed half the distance from the car as the passenger side. Took over 2 full turns of the adjustment screw to get it right. (yes, the passenger side aim is correct)

Critter

You are not getting a warning because the alternator is covering up for the aux battery, if you wish to test, turn key on and press the brake pedal about ten times and then hold the brake down for a few minutes this will give the aux a workout without assistance from the charging system. Better yet get it load tested. Just sayin!
Really 11 years old, change the aux battery, will be money well spent
Other than that "Happy Trails" save up some cash for the tow

starbrite

Thanks Critter......yes, change aux battery now. No "Happy Trails" for me