my battery light comes on and off as well...usually at idle it stays on, then goes off as i drive but if i apply the brake it comes back or once i hit around 3k RPM...alternator and starter are brand new i have test specs for both, and my battery is brand new red top.

 

I moved your post to your own thread. Even though your problem may resemble another, always start a new thread for a new problem. It's less confusing to responders.

Suggest having alternator tested at auto parts store.

Alt light coming on at idle suggests alternator rectifier is probably partially failed limiting output at idle to too low voltage to prevent Alt light from coming on. New alternator likely needed. Yes, despite it recently being replaced.

Another possibility would be a slipping crankshaft pulley not supplying enough belt speed at idle to turn alt adequately. Make a radial mark from bolt outwards across the rubber ring in the crankshaft pulley and run engine for a while. If the inner and outer marks move (cicumferentially) relative to each other, then crankshaft pulley needs to be replaced. This happens on high mileage vehicles.

good luck

 

thanks for moving me to another thread, reason makes sense. i was thinking the crank pully as well so i chacked it last night, all is well. as for the alternator, i made it and tested it myself at work. This issue was present before the swap, and hasn't changed. tonight when it cools down, im gonna trace wires, see if maybe a bad wire is the cause.

 

Were you able to find anything on this? Mine does it to. Batt is good & alternator is fine as whell. Maybe up the gauge of the alternators charging wire.....

 

Start with checking the voltage at the battery and at the charging post of the alt when the car is at idle and the light is on. What are the readings of each using a volt meter?