[rich weyand]

Think of it this way. I have a water tap on the side of the house. I measure the water pressure as 60psi. If I put 500 feet of garden hose on it, and measure at the end, I get 60 psi. But when I turn the water on I get much less water out of the end of 500 feet of garden hose than I would if I was at the house right at the tap.

The resistor is 500 feet of garden hose. The three fan positions are LO (through the whole resistor, 500 feet of garden hose), MED (through half the resistor, 250 feet of garden hose), and HI (bypass the resistor, straight from the tap).

52A (black w/orange or orange wire) is the wire that bypasses the resistor. It's busted somewhere, or that position is broken in the switch. Only way to get what you are seeing.