2016 F150 blowing hot / cold / hot / cold .....

[Jim Oaks]

When I got in my truck last night I noticed that my heater was blowing hot, then cool, then hot, then cool......

Any suggestions?

 

[Snoranger]

Probably a blend door motor cycling from one extreme to the other. When it starts doing it, reach up under the dash and put your hand on the blend door motor. You should be able to feel it turning.
I’ve never ran into that issue, but it sounds like the blend door can’t sense it’s position.

 

[rubydist]

Either that or it has turned into the typical female...

 

[SenorNoob]

Couldn't large bubbles in the cooling system cause that too? Does that model have heater core bypass valve too?

 

[bobbywalter]

Boost in the degas bottle?



I have had pens drop down in the defrost and pop motors and gear boxes on the doors.

 

[Jim Oaks]

Pulled into a parking lot tonight and noticed the heat was blowing cool air. Reved up the motor for a few seconds and the air turned warm and stayed warm.

 

[bobbywalter]

Sounds like a bubble. What's the coolant look like?