Hey everyone,

Need some help, going crazy trying to figure out the problem with my C-5. The battery keeps going dead, I have replaced the battery and still have the same problem, if the car is not run for more than a day the battery goes dead. Anyone else have this problem or have any ideas what to look at?

 

Thanks! I will check the items you listed and the items on #590. Will update if the problem is found.

 

Same situation here. I'll be using this

 

Do a current draw test to see just how much current is being consumed avter the BCM goes into the sleep mode.

Please post the current reading.

BC

 

i had the same issue a month ago.......bought new battery, same thing.....but i did have a start lug (when i started the car it was kinda groaning to start....sorry i can explain better)....i read a post here where the starter solenoids have issues that could lead to the same symptoms. i replaced my starter and its cured.......it now starts with a hit pitched fast sounding whiz (again best explanation i can think of for sound).....no more battery issues, no more starter lug

i do have a battery tender i put on it also if i don't drive for 3 or more days.

not saying this will solve yours, just sharing what worked for me.

good luck

 

Will post reading as soon as I can. Thanks Bill

 

AMEN brother.

I am sick and fed up with this stupid battery issue. My car has for years drained a battery within 2wks of not being driven, but recently it has gotten worse.

 

The three C5s I've had experience with (mine, two friends', all low-mile garaged cars) have all been hell on batteries. Each will drain a new, fully-charged (12.7 volts) battery down to about half-charge (12.2-12.3) in a week, and down to draggy-starter level in two weeks or so). Each car's drain has checked out within spec. I never could figure out what was going on (some intermittent thing?) so I and friends just keep them on battery tenders/minders/Ctek, etc.

 

Be sure you haven't twisted that interior dimmer **** all the way right (or is it left?) till it clicks. Doing that will create a 200+mA draw that can drain your battery in a couple days.

 

Hey Bill,
I did the draw test,twice as you described and both times the reading was at .01-.02 after about 20-25 min. I did pull the amp fuse and seat breakers last night and the car started fine this morning. I just need to find out which one is causing the problem. Will let everyone know when I figure it out.
Thanks Again for all the info.

PL

 

To all the people that are having C5 battery drain issues. There are reasons that are causing your C5 to have a weak battery issue with in days or weeks. The hard part is figuring out what is draining the battery if its very intermittent.

I have experienced numerous C5's that will start the car with minimal starter drag, after the car has set idle for 30+ days.

There are several occupant operated controls that can and will cause intermittent severe battery drain.

One is the seat multifunction switch. It can have a weak return spring and allow the seat to continue to drive until the battery is dead. The reason it doesn't burn the motor out is the circuit is protected with a resettable thermal circuit breaker. The lumbar motor is another common run on suspect.

If you suspect your that your seat is or could be causing your drain issue, set it to your desired driving position and unplug it to test that theory. NOTE! That will cause no comm DTCs but no harm or performance issues. It will also effect your memory function if you have that RPO.

Another very common problem is the very one that "wcsinx" pointed out. If you accidentally turn on the interior lights using the dimmer switch during the day, the interior lights will stay on and rapidly drain the battery. Examine your car when it's in the dark and see if any lights remain on.

Your head light control module is a constant current draw module. When you connect the battery you can see the headlight doors jump. Check that circuit for current draw. If you insert an AMP METER in the headlight control module fuse position you can directly measure the current that module draws. That test can be used to measure any specific circuit. Just make sure that the meter you use can handle the MAX current rating of the circuit in test.

Do you have a good battery? Take the battery out and have it tested to make sure that it can support a constant .02 amp draw. Have it checked for CCA and Reserve Capacity. If it fails those test, it will not start your car properly over time.

Ive helped quite a few people who's batteries would drain in days find the problem. Once they find it, they cant believe that they don't need to have a battery tender any more.

Keep looking and posting results.

Bill

 

I'm guessing the alternator is the problem. Anyone else???

 

The alternator on our C5 are pretty reliable. The wiring that connects the alternator to the electrical system is commonly the problem.

-What does your IPC Volt meter read?

-What does the DIC volt meter read?

-What does the voltage directly on the battery terminals read?

- What does the voltage on the BATT terminal on the back of the alternator (under the rubber boot) read??

The alternator & battery are directly connected THRU the main connection on the starter solenoid. The RED wires are the connection between the battery and alternator. If that connection is corroded burnt or compromised, the alternator will have poor or no output:



To test this problem run a jumper test wire from the POS battery terminal and connect it to the the BATT terminal on the alternator. If your battery voltage on the DIC and IPC increases, find out what part of the charging circuit is compromised.



BC

 

Now how did I know that thats possible?

 

Oh I found out the hard way too.

 

Hey Bill,
Great info toy put out. Update on my battery issue. I put the amp fuse back in yesterday and the car seemed fine this morning, looks like it may be one of the seats, I will put the breakers back in one at a time and see which one is causing the draw.
Thanks again.
PL

 

Thanks for all the info. It may be one of the seats causing the draw. I did the tests that Bill suggested. You can see results on my reply to Bill.
Thanks for the help. I will let everyone know when I figure it out.
PL

 

Hey all,
Sorry i have not updated on my battery problem, it turns out that it is something with the left seat. I have not tracked down the exact problem yet, just havn't had the time but my battery has not gone dead with the breaker for that seat out.
Thanks again to all for the tips.
PL

 

Another reason why this is the best forum on the net! Great reading! Well done, guys!