2007 Pontiac Grand Prix Voltage flucuates

2007 PONTIAC GRAND PRIX
75,000 MILES
Avatar
RDB5380
  • MEMBER
  • 1 POST
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?
Aug 11, 2013 at 10:40 AM
Advertisement
Avatar
JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 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?
Aug 11, 2013 at 2:12 PM
Avatar
MADMIKE1735
  • ✓Experienced 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.
Sep 14, 2013 at 2:42 PM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle