Troubleshooting High Pitched Sound......

2006 Town and Country LXi is emitting a high pitched sound when inside the vehicle. It does not vary pitch or volume when the accelerator is pressed, nor is it affected by turning the radio or climate control system on or off. It can be heard outside the vehicle as well. We cannot pinpoint where it is coming from, but think it could be the exhaust. It will happen for awhile, then completely go away, then return. Any ideas or suggestions?

Thanks in advance for the help!

Inside the cabin and not under the hood correct? Just while moving? Can you nail down an area? Front back, left right? Pull accessory fuses till it goes away.

Have you removed the serpentine belt and run the engine for a little to see if that eliminates the noise???? It will not hurt the engine to run it without the water pump turning for a like 2 minutes.

Inside the cabin and not under the hood correct? Just while moving? Can you nail down an area? Front back, left right? Pull accessory fuses till it goes away.
The sound is noticeable inside the cabin. It can also be heard outside the vehicle. We think that it is originating from the rear of the vehicle. The tone is similar to the one that is audible during a storm warning (on the radio).

Fuel pump? It's in the fuel tank at the rear of the van. They can make an audible whine before they fail. It runs at a constant speed when the key is in the "run" position. Pump speed doesn't depend on engine speed. When you hear the noise duck your head down near the fuel tank.

If it's not that it could be wheel bearings though they usually emit a low piched grind or moaning noise. Could be a motorising door or window actuator. Pull the fuse and see if the noise stops.

BTW -Born and raised in Michigan City, Indiana way up north.