Setting 2 only, and you've replaced the blower resistor?
- (Just so others know - it's a resistor array, but with bigger wattage resistors - Some Climate control units use a semiconductor to drop the controller voltage due to the size of the blower and the power requirements it has - requires several 10's (not 10ths - 1 X 10 = 10 Amps) which is more than some resistor arrays can load)
The if there was any sort of hit impact or other shove or strike against the AC head unit - your control panel - then the control panel will have to be checked out - the blower "sinks" power thru all of the resistors on setting 1, but on 4 it's completely bypassed (Full current to motor) - so for it to work on 2 means the array conducts power thru it - so the issue then turns to the controller head unit and it's switch.