2007 Pontiac Grand Prix Voltage flucuates

Tiny
RDB5380
  • MEMBER
  • 2007 PONTIAC GRAND PRIX
  • 75,000 MILES
My battery voltage flucuates between 14.4 and 12.6 when driving. The more things I have on like lights or a/c the better it is. I have replaced battery, belts, and alternator which the regulator is connected to. I dont know what else it could be besides a short somewhere. Is there anything you can suggest to figure it out?
Sunday, August 11th, 2013 AT 5:40 PM

2 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Do you mean the more electrical load you place on the alternator, the higher the voltage?

If the car is at an idle in neutral and nothing electrical is on, what voltage are you getting?
Was this
answer
helpful?
Yes
No
-1
Sunday, August 11th, 2013 AT 9:12 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
Your alternator will only charge when it sees a need to. This fluctuation you describe is normal. It cant always charge the battery, if it did, it would be overcharging it. Thats why when you have your acessorys on, it stays around 14v. It needs to keep up with the demand.
Was this
answer
helpful?
Yes
No
-1
Saturday, September 14th, 2013 AT 9:42 PM

Please login or register to post a reply.

Related Serpentine Belt Replace/Remove Content

Serpentine Belt Replacement
GUIDE
Serpentine Belt Replacement
Need to change your ser­pen­tine belt? This is an easy job in most cases. There are sev­eral names used to de­scribe a ser­pen­tine belt, in­clud­ing: drive belt, poly-v belt, multi...
VIEW MORE