My 02 Grand Caravan makes noise when AC is turned and in Drive but stopped at a traffic light. The noise goes away when I am driving. It's pretty loud and annoying.

 

Typical 4th generation noises at idle are the alternator clutch and the A/C clutch. Post a video so we can hear it or have someone knowledgeable look at it.

 

Not that I know what it is but does it sound kind of like a like sub-woofer a hum? If you hold the brake and just touch the gas a little does it stop?

I have an 02 and it has this, kind of an in cab resonance. I be jammin my radio most of the time though and don't hear it.