Most here would recommend Beaver Coach Sales in Bend, if you intend to wait until then rather than seek earlier assistance. What's haywire is likely not peculiar to Roadmaster, though, so perhaps if you'd like it repaired sooner you just need to find a more competent local facility.
If you decide to wait, there are a couple others in Bend also quite familiar with Roadmaster or most any chassis. Your quarterly copy of Beaver Tales will show them as club supporters. Whether one of them or BCS, that is their busiest time, so call and schedule well in advance.
It could be a ducting gate issue, electrical or mechanical, esp. since you have neither temp. control. But then ours has never been particularly good at either dash heat or cooling, as I've heard others report about theirs. In extreme ambient conditions, many just go to genset and roof air, or diesel hydronics to heat on the road.
Joel
