thought i needed a new blower resistor for the blower motor as the #3 speed on the dial for the fan control speed switch wasnt changing from the #2 speed. no brainer, though it was the resistor, changed it out for a ford resistor and to my surprise there was no change in the #3 speed. further diagnose and teardown led to the speed selector switch as the fault, which as far as i know is not available as a replaceable part but instead u need to replace the heater/ac control head . teardown of the switch led to the fix.

i made a video of the process and repairing of the switch

 

If all the speed positions work except Hi speed, , you might want to look at a "High speed blower relay" that is usually mounted on the firewall n the engine compartment.
The blower motor requires a considerable amount of electrical power to operate at high speed and a relay is used to provide this power directly . It saves the switch contacts

That relay should be checked and verified capable of working before getting involved in anything else.
The resistor is used only when any speed other than high is selected/required.