I have a 2004 ford focus zx3 PZEV and when I turn my headlights on they flicker a little. This also happens to the interior lights as well. At idle when the rad fan kicks on the lights dim significantly until I start to drive again. I used a multimeter and with the car off get a reading of 12.4 volts. With the car on and no lights, radio, AC, it bounces between up to 14.2v and 14.4, with all those things on after about 5 minutes it bounces between 13.6 and 14.2v. It eventually got as Low as 12.6 and stayed more constant.
Read more: Is it my alternator?
