[RIP]

Shooting from the hip I would suspect something in the accessory relay circuit or the Front Control Module, better known as the FCM. The FCM controls the grounds to the blower motor relays and to the accessory relay which paths power to the radio and power windows amongst many other things. Can't count out the Body Control Module (BCM) either. It is a player in amost everything electronic in the van.

I have read about corrosion problems found at the FCM connection on the Integrated Power Module (IPM). That's Chrysler lingo for the fuse box next to the battery. Usually it's been associated with lights problems but, still I would inspect that connection. The FCM is attached to the front of the IPM.

Next time it happens see what else doesn't work. Might help find the smoking gun.