Know one can tell me what is worng!

[kcsweetpea31]

I have a 1999 Mitsubishi Mirage DE, and one evening i turned my lights on and slowly they became dimmer and dimmer, after turning the car off it would not even turn over. Okay got it jumped started went to Advance auto and they put a new battery in and checked the Alt. and they said it was fine, well it was not stilling not staying 100, lights getting dimmer etc. We finally replaced the Alt. still doing it. Took it to a shop who specializes in this and they said out orgn. Alt was fine, so they put that one back on and checked the belts, one was slipping fixed that, but still doing the other. Help anyone know anything???????

[evoryda]

did you check the wires to and from the batterys positive side, cause they may be worn and grounding itself, or it could be grounding itself by the battery tie done too so make sure its not touching the positive post.