Nissan Repair: Fan Switch on Dash, nissan altima, fan switch

Question
1996 Nissan Altima
Fan Switch only works on #4. I replaced entire assembly in dash with a recycled replacement part & it did the same thing. Any suggestions?

Answer
The switch is not the problem.  There is a resistor box under the dash on the passenger side.  It is under the dash close to the blower and this is what regulates the fan speed when you move the switch on the dash.  They could not put it behind the switch as it gets hot and needs room so it does not overheat.