lights dimming out?

hi guys, well i have a 2005 neon and the last couple days when i drive at night , i turn the lights on and the interior lights and the headlights start dimming, while at the same time the engine will fluxuate like idle real low then jump up to normal. i replaced the altenator 3 months ago. it will do it , then it might wait a few days and do it again (the lights dimming). but the last three nights its done it nonstop. also when the lights go dim the radio starts cracking and a/c will almost turn off.... im stumped any feedback would be great thx

hi.try to clean all the ground conections (sandpaper).Make shure battery conections all good and wires .Hope it will fix you problem