Well to add to all the other problems I'm having with my pos now when I'm driving at night about every 10 sec. my headlights will dim for like a split second. It's almost like a glitch or something.lol When it does this my volts gauge drops down one line to 14. It sits right above the middle. Does this sound like alternator or ground problems? Thanks for any input.

 

It sounds like the alternator. It might be a voltage drop when your A/C pulls in (A/C compressor cycles in defrost), or some other device starts. Do you have electric fans? Otherwise you would think a ground problem would show up when you hit a bump, if no device starts at the same time as your voltage drop. You should add a signature that describes your truck, it is hard to tell what you have from your description "my pos".

 

Alternator or ground. Make sure the connection on the back of the alternator isn't loose.

 

Sorry buddy it's a 06 Sierra cc and yes it has e-fans. I don't think its from the ac as its cold here and no use for it. I dont think its cuz of the fans dunno. A while back when riding it would drop down to 12 and then back up to 16 and kept doing that. Now it stays on 16 and when my lights blink it drops to 14 then right back up etc. Are the e-fans famous for killing the alternator? I think it may be the alt. How long do they usually last as my truck has 82,xxx miles and I am the second owner.

 

5.3L also

 

See above. If you have the switch in "defrost" or "mix" the compressor cycles to dehumidify and help clear the windows, regardless of your temperature setting.

 

Your gauge is reading 16? If that's correct than it's overcharging, 14.7 volts is about the tops that an automotive charging system should see. Sounds like the alternator has an issue...

 

No the defrost is not on. Bud your prolly right it sits right above 14 and its not 16 but when my lights flicker it drops it down to the middle (14) then back to normal.