Headlights dimming

[jj79]

when i press the brake the headlights flicker and dim for a second then go back to regular brightness. could this be a short or a grounding issue? could this issue be the reason for my left blinker light to go faster when the headlights are on but not with just driving lights?

[gothstone]

sounds like a weak battery or alternator. Most auto parts stores can check both for you for free in the parking lot.

[Daox]

I'd check the grounds. There is never any harm in cleaning them up.