Hi Bruce and
to the forum.
Do the three battery gauge LEDs on the throttle still light up?
Try unplugging both of the brake lever connectors and see if it makes any difference.
Turn the power off and then disconnect the BAC-601 Smart Display unit. Power the motor back on again and see if it that makes any difference.
Make sure that the ends of the unused wires for the horn, lights, pedelec sensor and reverse are not exposed and touching together.
If possible, check the +5V supply for the pedelec
(measured between the Red and Black wires) and see what voltage reading you get
(it should be ~4V).
Alan