My 2016 (6 months old) Frontier seems to be having heat problems. I put the heat on recently and it started warm (on temp 72), but then started blowing cool air after about ten minutes. Put it up to 75 and still felt cool. This has been going on for about a month and today I finally brought it to the dealers. They said they bled the system to get the air pocket out. Drove home, cool air again. I have to put the temp. dial up to 90. To me that isn't right. It should blow warm air at 72 and very warm around 80 and hot at 90. Anyone else have this problem? Also, the air circulation button light is always on.