First post on this forum as I recently purchased a 27RL after selling the Keystone and downsizing. Spent a few days in over a 100 degree temps and decided I want to add the second AC in the bedroom. The tech at the RV dealer (doesn't sell GD) asked if I could find a thermostat wire at the ceiling opening to determine what control is needed on the AC unit. I found a round tan wire with about 6 very small wires inside and it disappears into the ceiling headed towards the drivers (left) side of the RV. There is no way to see where it goes so we can attach to a thermostat control. Does anyone have any advise at to where it goes comes down a wall or how to find it?