When the car is cold and i turn it on the battery light is on although very very very dim. but goes away after the car warms up. Also i have turn on the lights to see if it gets brighter when its on but when i do it goes away?

I'm asking cuz i plan on a long trip real soon.

 

change it soon as possble same thing happend to me light came on and as soon as i started driving it went away 2 days later im on the high way and the cars starts to strugle all my **** started dimming and she eventualy dies at the light bad altinator change yours asap and if you think its the altinator just take it out bring it to auto zone they can test it and youl find out for sure

 

check your belt first