Anyone else with an 11-14 F150 have a noticeable drop or increase in the HVAC fan speed while braking or accelerating? I replaced the fan speed regulator per many of the threads on here about it being stuck on high and other related issues.. no dice, might be slightly better but still very apparent. Even came across a thread that seemed to have the same issue and swapping said part resolved it for them. Any ideas where else I should be looking? Everything works fine but this drives me nuts especially in stop and go traffic.

 

Try the blower motor resistor. Pretty simple to change, just drop out the glove box.

 

Sorry, should have said resistor. In the short drive I took after replacing the part you mention it was still there, though slightly improved.