question for HVAC guys

Unless the motor is heating due to something like dragging bearings, and tripping an overload, an intermittent motor is unlikely. Much more likely to be a bad relay, sequencer, or if newer and a single control board, "something on the board"

There is normally no proving for blowers in older electric furnaces. The elements normally have individual hi limit thermostats, in series with one time protectors. These look like diodes, and are thermal fuses.

A diagram of the thing would tell the story. I know you don't want to hear this, but for safety reasons..........as well as keeping the service guy in a good mood, LOL........it's REALLY not a good idea to "lock up" access to a furnace