I have many K-line diesels with can motors. They are mounted opposite each other and are wired accordingly to spin in the same direction. I would assume you can do as you propose. I wire all of mine in series to slow them down. The blue and brown wires off the board are the power leads to the motors. Yellow and blue are the hots from the motors. These show after I changed them to series.
I'm not familiar with ERR so someone who is may provide more info.
Bob
