Howdy everyone. First post. I tried searching and couldn't find anything. We have a 2009 Forester and noticed now that the weather is getting cooler that the heater only blows hot air when the temp knob is turned all the way up to 85 on the dial. Any less, like 80, and the air blows cool and warms a little, then cool and warms a little, and on and on and on. The AC is great and the heater worked fine last year. Standard oil changes and brake jobs is the only thing that's been done to it since last using the heater. I'm an air cooled guy so I haven't a clue as to what could be going on in my wife's car, but I'd like to try and fix it.
Any ideas?