She blows cold until I turn her way up. Why?

[Arlo]

Hello all,
I have to turn my temp to about 81 to actually get heat out of this thing. The weird part is that its intermittent. Some times 77 gives me plenty of heat.

This happens while driving and my coolant lvl is not low.

I'm thinking I have air in the line or the thermostat has failed on me.

Thoughts?
Thanks

[Ilya]

When I took my 2011 apart for some dashboard stuff...I had a similar issue as well (heat only worked at 90) because I unplugged the panel under the steering wheel which has a little grille on it...presumably some kind of temp sensor? Once I plugged that back in it started working again.

I'm assuming the Y50 is similar?