Good evening. I'm not sure if this is normal or not. My 2016 F150 3.5l EcoBoost XLT has a heating issue, I believe. If I turn the temperature control **** all of the way to Max defrost the heater blows hard. If I add floor or vents the power goes drastically down. Barely blows out of the vents. When I brake or turn the power will pick up and then go away. I'm unsure if this is normal...actuator door? Blend actuator?

Thanks

 

Does your XLT have auto climate control? If so, the fan got to max speed because you asked for a high heat demand. The only way for that to happen is increased airflow.

You experience lower air flow when you've selected multiple vents because the air is blowing at "X" volume. You've asked the air to discharge from more locations and the speed of discharge cannot be maintained at equal pressure out of additional vents.

The braking thing is a bit of mystery to me, sort of. Back in the day, vent doors were vacuum controlled. You have different vacuum at braking and driving. When vacuum is reduced the doors would slightly change position. I think the blend doors and vent doors are electric now?

Notice when you are holding the brake pedal, at times it will 'sink'. That's the result of vacuum being made by the engine and how the vacuum brake booster is affected.

 

It does not have automatic climate control. One zone manual. Even if I only select floor or vent, it will not blow as hard as defrost max. It's also odd that I can hear it blowing harder intermittently when braking or turning. I understand that the more vents I select the less pressure I should feel from individual vents. But the motor seems to not be blowing as powerfully...ie it isnt as loud as when on defrost.

Thanks

 

In my truck if I change the air distribution settings while the fan is at max speed defrost, the fan slows down, the actuator doors do their thing and then the fan ramps back up to max speed. The air flow does indeed decrease at the defrost vent but I’m pretty sure it’s normal. My thought is your blowing a finite volume of air from basically 2 openings. When you add more openings the same volume of air now has at least 6 additional openings to flow from.
I have never noticed any change in air flow with the use of the brakes. Once the HVAC doors have gotten into position the fan and flow stays consistent in my truck