Blower running. No air coming out after driving

Blackout

Dat Rust Bucket
Dec 18, 2015
121
11
18
West Michigan
Just what the title says. Happens with both AC and heat, after about 20-30 mins of driving with AC or heat on, air stops coming out but the blower keeps running. If I turn the hvac off, wait about 10-15 mins and turn it back on, it works fine again for another 20-30 mins. Occasionally it also sounds like rushing water, whether air is coming out or not.

Truck is a 2003 1500 LT ext cab with digital hvac controls front only. When it's working l, ac is ice cold and heat is hot as fuck. Any ideas? Winter is coming and I'd kinda like to have reliable heat