2011 F150 Lariat Screw w/Ecoboost - Recently my heat and A/C started running full blast when I turn them on and doesn't seem to respond to the temp setting. Previously, the heat wouldn't blow until the engine warmed up and the fan speed would reduce once the desired temp was reached. Now it seems as though the system (both heat and A/C) are either on or off with no moderation based on the interior temp. Anyone have an idea what I should look at?

 

Just wanted to pass along an update for anyone that might be interested. The HVAC blower control module was bad. This is apparently a common problem. Pretty easy to replace, it's in the A/C plenum right behind the glove box.

 

Easy to replace if you don't have AUTO A/C..

if you have the auto A/C, theres a blend door UNDER the box, that required full removal of my dash. That was a fun day!

 

He has the auto system. You're confusing one of the blend door actuators with the blower speed control module.