I have a 2019 F-150 V8 and noticed while the AC was cold ~38 to 40 degrees coming out of the vent, the fan did not seem to go as fast as I remember it and it's really noticeable in the summer heat in NC.  I bought an scan tool that Scotty reviewed and sure enough, the Blower Motor Speed shows as 80.39% when the Max AC button is engaged and the fan speed on the dash is up as far as it would go (7).  I can read the live data and do the actuator test where I can up the fan speed in the app and sure enough the fan speed goes up to 100% and you can hear and feel the increase in the air speed.  But I can't get the same results using the controls on the dash.  I checked the blower motor fuse under the dash and replaced it just to be safe.  I then read that the resistor may have gone bad.  In the case of my F150, you can buy it separately, you have to buy the entire blower motor assembly (FL3Z 19805E) at $400 + labor which I just did today.  I got it back from the shop and it didn't seem to be blowing out the air any faster.  Shame on me for not taking my scan tool to the shop and confirming it before I left but sure enough when I scanned it again when I got home, I'm still at  80.39%.  And I can again within the scan tool up the speed to 100% but no luck using the control on the dash.  I will contact the shop in the morning but I'm hesitant to take it back to the same place that didn't fix it correctly the first time.  Any help would be greatly appreciated.  Thanks