2003 Dodge Caravan whining noise

2003 Grand Caravan. Has a whining noise that doesn't change as car warms up, or when steering or accelerating. Remains constant no matter what your driving conditions are. Tried all the buttons on A/C with no affect. Sounds like it's coming from underneath the middle of the car where middle seat is. More prevelant on passenger side. Doesn't happen with key turned to just accesories. Anyone else had this and knows what it is? It's getting kinda annoying to listen to.
Thank you for your time.