I have a 72 Cutlass, 350 with 'air'. The fan has 4 speed settings. I have only the lowest speed and the highest speed. The middle two speeds are not functional.

Besides the resistor pack on the blower, is there anything else in the circuit that could possibly cause this?

If I have to remove/replace the blower, is there any tricks to making this an easy proceedure?

Any and all suggestions are appreciated.