Bright Caravan Park

2005 3.3l Dodge Grand Caravan lately my headlight was burning. I notice that now when I use the windows or step on the brake lights low. also if you slowed down in the park for a while, suddenly all is bright Sun then again, I tried to watch the speedometer. and it does not fall any diet, even if the car sounds like it is. Is this a problem with my voltage regulatora and if so, where it is on this car. i looked at a site referred to a person the volt reg. was built into the PCM. and the site even said another person was built in the alternator aaaaaa thank you for your help.

Maybe one or the other. Some alternators have built in voltage regulators. Although construction just replace the alternator, If this is not a test voltage output of the alternator to determine if it works.
Check all your cable connections between the battery and alternator before anything. it could be a bad connection.

Loose or cracked belt alternator or voltage regulator is erratic.