99 C1500 Suburban Lights flickering inside and out
 

My C1500 5.7L Vortec lighting flickers very faintly on inside and outside lights. I check alternator and it registers 13.5 to 13.6 constantly. Nothing below that or above. Was there a TSB about this? Maybe I missed something. Any other ideas?
Thanks.

Re: 99 C1500 Suburban Lights flickering inside and out
 

I would clean the battery cables, especially the ground.

Re: 99 C1500 Suburban Lights flickering inside and out
 

Look for any swelling or distortion in the casing/insulation on the battery cables near the ends. Corrosion can start at the end and work it's way down the casing out of sight. Also check the body to frame and engine to body grounds. IIRC, back of passenger side head and roughly straight below that on frame.

Re: 99 C1500 Suburban Lights flickering inside and out
 

you look at the voltage regulator at all? also like 83GMCK2500 stated...check all major ground points