My car has been having a strange voltage drop for the last week or so. It only does it at night when i have my lights on. When ever i have to come to a stop and i put the car into neutral, it looses all voltage, lights flicker on/off, dash lights flicker on/off, stereo does it, the whole car does it. After a few days one of my fog lights went out. It still lost voltage every so often, but not as much. i replaced the fog light and now its doing it again. The weird part is that it will only do it when the car is warmed up. When its cold and the idle is over 1000rpm it will never do it. When it is warm, the idle is around 850-900rpm, thats when is starts to do it. I am not sure if i have a short somewhere, or if my alternator is going bad, my idle is to low...i need some help please.

 

Have your alternator tested.

 

Also check your battery.

 

Got the alternator tested, it came back with a clean bill of health. I checked the battery with a volt meter with the car off and it read 12.3 volts..a little low. So i turned the car on and checked it. Read 12.85...again a little low. i noticed corrosion on the positive terminal (minimal amount, i barley noticed it) cleaned it all off and everything is back to normal now thank you for the help guys