[A A Ron]

We purchased our barely used 2021 3781 last spring and it has been great. The only issue that we had was the furnace exhaust was ridiculously resonate. This wasn't an issue as the heat pump in electric mode worked great and we just used that. We took the trailer back to the dealer for some pre agreed repairs and mentioned the exhaust to them. They said they could look at it. Well they did make the furnace better by "tuning" the exhaust a bit. BUT... Our system will only run in furnace mode now. Even with outside temp showing in the 60s the furnace will kick on when electric heat is selected and nothing we do with controls will get only the heat pump to operate as it did before. I have taken it back to the dealer a couple times and gotten the same shoulder shrug. I assume that when the furnace was worked on the tech jumpered the furnace and did not remove that jumper but damned if I can find it. Any ideas of how to get the heat pump working properly again??