MY blower recently became intermittent and then pretty much stopped working. I took some voltage measurements at the main power plug (at bottom of motor housing) and at resistor block (4-pin connector at top of unit housing). I do get +12V to the power connector; here is what I measured at the resistor block connector:

Switch Position 1: +12V between Pins 2-3
Switch Position 2: +12V between Pins 2-4
Switch Position 3: +12V between Pins 2-1
Switch Position 4: 0V between all pins

Can someone please tell me if this is a switch problem? Are the resistor block mesaurements above expected? I would appreciate any other test/debug info so I know what to replace.

Thanks.