2001 Nissan Maxima Blower motor working intermittently

Blower motor working intermittently for about a month now. I have a 20th Anniversary Maxima with auto air controls. I've replaced the blower motor relay and blower motor amplifier (module assembly). It's still working part time, and works on all speeds when it does blow (so I don't think it's the resistor). The blower hasn't cut out while running, but I'll find it dead much of the time at start up. If I reach under the glove box and tap on the blower motor or drive the car over some Zots dots (lane marking dots) with the right side tires, the blower motor starts up and stays running until I shut the car off - then it's 50/50 when I restart. I'm sure there is a short somewhere, but is the motor bad, or if not, where's it shorting out?