Swapped out an older beckett unit with a Newer blower motor unit. beckett control module R7184B 1032.
The electrical lines has two sets, one to the upper furnace (to the air blower am pretty sure) and another set of wires, for power I think.. It's the second set am confused by. It has two blacks, a white, and a yellow. All thicker gauge wires. 115VAC. I think the two blacks tie together, and white.. to ac power.. but am stumped what the yellow wire is for.
If it's of help, the first set of wires are smaller gauge: red, black,green,white.