ive been having charging issues with my 07 grand prix gxp. this all started about 6 weeks ago. i was driving to work, and charging system failure came across my dic in the dash. then it flipped to the battery section and showed the battery or charging system had something like 10.3 volts. got it to work, fine, went out that nite and was on my way home i was watching the battery like a hawk, it stayed at 14.84 the whole way home.

a few days passed, and the battery thing would fluctuate between 14.84 to 13.81 constantly. then it got to the point that anywhere i drove it, it would stay at 9.84. so i went ahead and assumed it was the alternator. took mine in to be tested at autozone and they dont have the ability to test these alternators. i went ahead and bought a new one being as my old one was kind of hard to turn. threw it all together, and drove it, and the charging system would stay at 14.48 all the time.

i let the car sit for a few weeks being as i bought a new truck, and just wanted to drive that. well i get in my car to goto work lastnite (27 mile one way) start out, volts are staying at 14.48, got about half way to work and i noticed the voltage was dropping by .10 volts every few seconds, would drop down to 13.01 then would gradually come back up to 14.41 again then went up to 15.10, then came down to 14.84 then leveled out at 14.48 again.....this all happens while the car is in motion as the voltage levels out at 14.41 at a stop

i dont think this is normal for it not to maintain voltage like this...is there something to look for? or is it possble this new alternator is junk?? thats where i hope one of you guys can help me with this....could it be something as simple as my battery taking a puke? i dont know how old the battery is, i do know it is a interstate, so i dont know if that is the factory battery or not. any help, tips or info would be helpful. thanks in advance

 

Do a search it is a common problem, usually it is the DIC acting up. Mine did the same thing a few years ago and everything is still fine even with the volts being in the same range as yours. I personally wouldn't worry about it.

*edit*-if you do decided to get a new battery get a Red Top, everything else gets eaten in our cars quickly because of On-Star always drawing power.

 

ok thanks for the info...the car starts fine when cold, so it is charging. but i do want to throw a nice stereo system in here at some point so im sure the red top will help with that too....i dont know if this is a issue either but when i open the door to get in the car i can hear motors running, it honestly sounds like the climate control opening or shutting flaps for the defrost inside of the car. i thought id throw this out there as i did some searching last nite, and have noticed people having issues with charging like me when their bcm's are puking on them...

 

the dic started acting up again. and stayed at 12.2v yesterday. so i finally got the opportunity to read the voltage. got my volt reader out, and it accurately read 12.2 volts also, which was what the dic was reading. so i doubt my dic is messing up...now back to my original question, what can be causing this???

 

Most shops will check the charging system for free and they have all the right equipment.

 

be careful who you ask about the optima's i just replaced a 1.5 year old red top after it started discharging on its own. also i have noticed my info screen showing ~13.5 while driving.. that group 35 optima is easier to get in and out of the car!

 

im still looking for a shop that will check the charging system for free. everyone around here wants a arm and a leg to test
its kinda pissing me off.

 

Take it to Sears.

 

didn't realize you was from iowa. looks like im about an hour and a half away in lake mills, if your in the area i could check it for free at the shop i work at.

 

thanks joe...ill try to do that next week. i have 5 12 hour shifts in a row at work starting tomorrow. ill pm you for more info

 

what exactly would a charging system test do for me? just tell me if my new alternator is junk? or can it go deeper than that? such as if my bcm was acting up? or what?

 

They test the alternator, voltage regulator and the battery. I'm pretty sure Autozone can test it for you and they never charge for any services like that.

The BCM isn't part of the charging system and the dealer would have to check that.

 

i have 2 batteris in my GXP, my voltage when i first start up cold will be around 14.5, then will slowly drop to high 13's. But i have a voltmeter installed and can see the readout on the dic can be a little off at times. not much maybe .5 at most. But then again we do have battery savers that are enabled by pcm.