Fan and stereo turn off randomly while driving.

(2010 Chrysler town and country touring)
As the title states, the power to my fan and stereo systems turn off randomly while I am driving. They always turn off and on together, which I think indicates that the problem is not in either of their individual wiring. They turn on for a couple minutes at a time, then turn off minutes later. It seems like vibration may play a role, since it turns off and on more frequently at a slower speed.

The cabin lights, odometer LCD, and ignition all work.

possible guesses:

Defective relay?

Issue with the onboard computer?

Wiring issue?

Thank you very much for your help!