2003 Yukon XL Recirculation Won't Turn Off

[RAWVORTEC]

2003 yukon XL. My wife called me and told me the A/C seems to run hot while sitting in the parking lot to pick up kids. She says she tries to press the recir. button, but it blinks twice and stays on. whats the deal?

 

[RAWVORTEC]

Coolant level was low. Filled it up, and it would stay cool when sitting still.