also check the RB (regen) contactor not conducting or closing when driving (regen picks up when this contactor opens diverting motor power from neg thru the 7 rec)

also an open or loose connection in the motor circuit

its series wound so you can check continuity thru the whole circuit from the 1rec to neg with the batt unplugged and working the fwd or rev and RB moveable tips by hand

also defective 1a (bypass) RB SP or FW can cause this
check for seized or binding contactors
and check the fwd and rev contactors for welded normally open tips

check the control wiring to the rb contactor too