After trying lots of suggested solutions I ended up in Shipshewana at National Refrigeration.
Leon checked out the ac units and found a wire chase 4” x 2” running from front to back thru the a/c units that was not sealed off when the coach was built. This allowed the a/c to pull hot air from the chase and put it into the coach. The smell was that of fiberglass getting heat from the top of the coach.
A/c working better than new. No smells, very good service at a price that was very inexpensive.
Highly recommended business
National Refrigeration Shipshewana Indiana