Voltage regulation issues

[saturntech95]

So as of recent my truck has been doing some weird things, mostly when my lights are on. All my gauges read incorrect and bounce. My altenator is about 6 months old Toughstuff 140amp(I think) and tested fine. The truck is perfect when no lights are on but if the parking lights are on it drops the volts a little at a stop but will still make 13 driving and rarely acts up. But if I put the headlights on then I maybe get 13 volts driving and it drops to about 11 stopped and ahe gauges are all a bit off and jumpy (flutter).

Has anyone run into this before?

 

[Mad Maxx]

I had this Problem On my S-10 Blazer, and it was the Alternator.

 

[RI Chevy Silveradoman]

Have you checked the ground wire? Sometimes a bad ground wire will do this.

 

[WarWagon]

Check the gauge fuse for corrosion. Flutter indicates a loose wire or AC via a bad diode in the alternator. Corroded positive battery cables can also do this esp where the alternator ties in.