Service battery charging system.

[bzubke1]

I have been getting this message on the dash off on on for the past few months. It has been becoming more frequent in the past few weeks. Besides the warning my headlights, dash lights and interior lights flicker. Most ppl in the car don't notice it but it's enough that I do. With the engine off they do not flicker so I want to say the battery is good. I'm guessing alternator but whenever the warning comes up on the dic, I look at the volt meter and everytime it reads just over 14 volts. I'm going to try and pull the alternatir this weekend and have it tested. I've never gone to start the truck and had a dead battery so I want to say the alternator is doing its job. I've checked the connections at the battery, they are both tight and not corroded. The ground by the passenger side cylinder head is also tight. Any other connections I should take a look at? If anyone has any ideas I'm all ears. Thanks in advance.

The truck is a 2007 yukon slt 4x4 5.3L, All stock. I did switch out the license plate bulbs for LEDs if that makes any difference.

 

[bzubke1]

Update: had the battery and alternator tested at autozone and both passed.

 

[Goodinblack]

Have the battery cables checked for resistance and voltage drop

 

[Ben]

Ground cable issue

 

[bzubke1]

I've noticed that when the service charging system warning comes on the voltmeter reads well over 14v. My guess judging by the gauge it was about 15-16v. This only happens every couple of days or every other.

I check all the cables coming off the battery. All seem to be tight. I haven't bought a multimeter yet to test the resistance or voltage drop.

 

[Ben]

It's the other end of the ground cable on the engine block

 

[Goodinblack]

I've noticed that when the service charging system warning comes on the voltmeter reads well over 14v. My guess judging by the gauge it was about 15-16v. This only happens every couple of days or every other.

I check all the cables coming off the battery. All seem to be tight. I haven't bought a multimeter yet to test the resistance or voltage drop.

http://www.tahoeyukonforum.com/forum/showthread.php?t=63936

 

[bzubke1]

Ben, if your talking about the one that is right there by the cylinder head on the passenger side, it is good and tight, haven't checked it for voltage drop or resistance yet.

Good in black, I'll have to take a look at that one a little closer. I traced it down to where it bolts to the frame and it was tight but I'll have to inspect the condition of the wire this afternoon. Was it a real pain to get the front bumper cover off or not too bad?

 

[Goodinblack]

I have done it so many times now that I can have the cover off in about 10 minutes

 

[GM Customer Service]

Hello bzubke1,

I understand that you are seeking technical advice for the vehicle issue you are experiencing. I am sorry to hear that you are experiencing this concern. As a customer service representative, I'm not able to provide much in the way of do-it-yourself information, so I'm glad to see forum members are beginning to step in with feedback. If you have any lingering concerns please contact me via private message.

Jennifer T.
GM Customer Care

 

[bzubke1]

Still haven't got it figured out. Did resistance and voltage drop tests on the battery cables, all checked out. Swapped the battery out with a known good one and it Helped a bit but did not cure the problem. Also had autozone test the battery and it checked out good but once I put it in the problem became slightly worse again. The truck starts and drives fine tho. One interesting thing is the lights will flicker but as soon as the electric fans kick on the lights are rock solid and don't flicker at all. Not sure what that would point to but thought it might tip someone off who has more experience.

 

[bzubke1]

Finally got it figured out. It ended up being the alternator. The battery light was on as I was passing an oreillys, so I stopped and had them check the alternator and it failed. Popped a new one in and all is back to normal now.

 

[tmac82]

Hey just curious...how did the fix go? Is everything still working after all this time? I have been having the same problem for over 2 years now. Have had all the tests done as well as the alternator replaced, battery replaced, and the problem keeps coming back. Lights are bright when voltage gauge is high (15-ish volts) and dimmer when gauge reads just under 14. Most of the time it's running just under 14. Alternator seems to be doing its job and is only 2 years old; old battery still tested fine but I replaced it on spec anyways.

Curious - what size of alternator did you get put in? I believe my new one was standard size...can't remember amp output.

 

[bzubke1]

I never had anything shut off on me or had a dead battery. My only symptoms were the charging light coming on intermittently and the flickering lights. The lights would flicker regardless of what the volt gauge was showing. It did however seem to be worse at idle. There was no rhyme or reason to when the charging light would come on, but it did increase in both duration and frequency over a period of probably 6 months until it finally stayed on long enough I could have the alternator tested while the light was on. I got the 160 amp alternator from oreillys. Was $170, takes maybe half hour to swap out.