The TOC should be in line with the carbon brushes, so a reading across them will include it.
Please do NOT be tempted to connect the motor directly to the mains. It will instantly attempt to run at at least 15,000 rpm. Given that the motor is designed for electronic speed control (ie to get to spin GENTLY), you are very likely to blow it!
Plug the loom back into the motor and test from the digiboard end. If you have circuits through field, armature and tacho, it can only be the board.
Which bit of "Unplug it" is causing the problem?
Stop eMailing me. This is a perfectly good forum - use it!