dimming lights

ok heres the scenerio all my lights pulse when im at a stand still when i accelerate it stops checked battery got like 12.52V is the altenator bad? thats what i would think any help is appreciated

Yep, that's the alternator.. well, actually it's the Regulator that's inside the Alternator.

Nothing to worry about for now, your dash warning lights will tell you if it dies.