I've spent several hours trying to figure out definatively what component is keeping my air handler blower motor from starting. To start, the system worked fine until we turned it off temporarily last night to watch a movie in peace, as the air handler closet is directly behind the sofa. My air handler is a RUUD, probably early '80s, original to the house. I changed the relay, as this has been a past culprit, but not this time. I then removed the blower motor and hooked up 220V to its two leads and the motor worked great. I'm now thinking it is either the motor's capacitor, although the capacitor shows no visible signs of demise, or the transformer. Something that has me perplexed is that with the thermostat turned to "off" and "auto" I show 125 volts/6 amps at both of the leads to the blower motor. If I turn the thermostat's motor control to "on" or the switch to "heat" or "cold" I have the same readings. When I ran the motor off of another 220V source I checked the readings and they were the same- 125V/6A at each lead. This has me wondering how the motor gets a signal to actually come on when the thermostat is turned to "on" or "cool/heat". There are no other wires running to the motor. One of the leads (black) goes from the relay to the motor, and the other (orange) runs straight from one of the bus fuses to the motor. Magic maybe? Also, the condensor is coming on when turned to "cool", so maybe this will rule out some possible culprits. Oh yeah, I also connected a new thermostat I had left over from a house I built with the thought that possibly there was a malfunction in the current thermostat, but that made no difference. I know this is a long post, but I like to be concisely descriptive to make up for my ignorance.