Hey my old mans truck is a 97 f150.

The switch for the fan speeds in the cab only works on the highest setting.

any idea if this is the switch that is gone, or the blower motor, or a resistor?

any info would be great thanks!

 

Usually a bad blower resistor assembly.

 

lay on passenger side floor-- look up under glove box. look for plstick block iwht resistors on it, screwed to air box.. has 4 wires to it ??