Black and Decker CM2040 Cordless Electric Mower. Motor will not start when switch is engaged. I have confirmed that the motor and the switch and battery are working correctly direct wired motor to battery, used continuity tester on switch and rest of wiring, connections, etc., and think the wiring and mechanical bits are correct. It appears that there's a safety of some sort between the battery and a circuit board, presumably checking for connection, voltage, polarity -- the components are all buried in resin, so not user repairable, so I am guessing this is what has failed. I can't find a wiring diagram, so seeking a way to confirm this theory. I'm pretty sure that the motor and switch are OK because I already bought replacements from B&D doh!. This time I want to purchase the right part. Any help or advice appreciated

Garden - Electric