I have a 2015 70D, and yesterday the heater started making weird noises. Initially, on my way home, it made sort of a repeated clicking noise - kind of like a fan hitting something. I turned the heater off the rest of the way, and hoped the windows wouldn't fog up. This morning I tried the heater, and now it's making a different noise - it sounds like servos repeatedly running for about a second, then stopping for a second, then running again, stopping, etc.. Do the ducts have servo-powered flaps? I'm wondering if it could be cycling back and forth between positions for some reason. I need to schedule a SC visit - unfortunately the nearest one is an hour away. Thanks for any advice!