SPONSORED LINKS

Fluctuating voltage

Tiny
GMCBLUZ
  • MEMBER
  • 2000 GMC SIERRA
  • 6 CYL
  • 2WD
What causes the voltage to fluctuate on the battery and lights flash on my 2002 GMC Sierra
Saturday, May 21st, 2011 AT 3:29 PM

3 Replies

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Test the charging system. Battery has a full charge and all connections, clean and tight?
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Saturday, May 21st, 2011 AT 3:57 PM
Tiny
GMCBLUZ
  • MEMBER
  • 2 POSTS
Yes, first thing I checked
Was this
answer
helpful?
Yes
No
Saturday, May 21st, 2011 AT 4:07 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
I did look at your TSBs, one of them said, "this is normal unless there is a proven fault".

I know that doesn't help much, did it just start doing this or has it been doing this all along?

With engine running, warm idle, all electrical loads turned on, what is the voltage reading across battery posts as compared to alternator bat terminal?

Are you saying, your headlamps go out?
Was this
answer
helpful?
Yes
No
Saturday, May 21st, 2011 AT 4:23 PM

Please login or register to post a reply.

Related Battery Content

How to Replace the Battery in a Modern Car
VIDEO
How to Replace the Battery in a Modern Car
Instructional repair video
Battery Connected Backwards
GUIDE
Battery Connected Backwards
It is easy to connect a battery backwards and it happens more than you think, so don't feel bad if you are here for that reason. Your car has safeguards built in to help...
VIEW MORE

Sponsored links