AC fan speed does not work on 5 max, changed the resister, no change, fuse is good under the hood, all speeds work, but 4 is faster than 5
The fan speeds 1-4 are controlled by the HVAC control module through the resistor network. The number 5 position is a direct path to the motor, it bypasses the resistor network.
If 5 is of a lower speed than 4 then you might have a ground or wiring issue. If everything seems fine then most likely something internal to the HVAC controller.