Austex1604

I recently bought a slightly used/certified 2014 F150 FX4 SCREW with 3.5 Eco. Today I noticed the AC fan speed seems to fluctuate for no apparent reason. When I have the fan set to high it blows really strong and steady. When I lower it to a mid or low speed, I can hear the fan blowing air through the vents and then hear the fan slow down drastically, then pick back up again. It does that many times per minute. When I hear the fan speed slow, I can also feel a decrease in the amount of air coming out of the vents. So far I have only noticed this when the fan is set to blow through the dash vents. I have not yet tried the other settings (floor/defrost) to see if it does it on those settings as well. Does this sound familiar to anyone?

Austex1604

Any ideas?

Feathermerchant

Not familiar. Manual A/C? If so, AFAIK it should not vary. If automatic A/C then it varies trying to keep set point.

Austex1604

It's an automatic AC but I never run it in automatic mode, always manual mode.