ive noticed that when driving, the headlights will dim a little bit, then go back to normal, all within less than a second. they dim to about the level they are at when the engine is off, which leads me to believe that it might be an alternator issue. I've checked and cleaned the 4 easy to find grounds around the engine bay. Is there anything else i should check? i tested the alternator, and with all accessories on, it holds 14.6V, and will all off its 14.7V, so it looks strong to me. Thanks

 

i havent figured out how to add a signature yet, sorry. the car in question is a 2002 Z28 M6. no electrical modifications, except LED bulbs for the 3rd brake light.

 

Red task bar at top of every page, left click on "User CP". On the drop down, left click on "Edit Signature". Type you signature in the "Your Signature" box.

Is the brief headlight dimming in synch with the A/C cycling on?

 

thanks! and no, its not. ive only ever used the AC during the day, and i only notice the dimming at night. its also not related to me touching any electric controls. almost seems like turning makes it happen sometimes, but i could be imagining that.

 

Could be a cell in the battery going bad....

 

i suspected the battery, but it seems to be strong. the car starts with no issues, and it took having the radio on for about an hour and a half to make the battery die.