hi you should take the back off the direction switch and check the contacts. direction contactor should activate as soon as you select a direction even before you touch the accelerator. check for a negative feed to the contactors. bo2s had a common fault,check the negative supply to the main control card socket and possible burn out tracks on the card where the black wires go in. also there was sometimes an extra card near the direction switch which checked switch was in neutral. you can unplug this and connect the other plugs together.if the contactors activate but still no traction check the accelerator unit. hope this helps.