Hi, the big cable "bolted to the floor" is the the main battery cable and connected to an insulated
terminal that goes through the floor, the other side another big cable continues to the starter
motor. If you are thinking of fiddling with that then disconnect the battery!! The wiring harness
that goes to the back is the bundle of wires wrapped in black insulation and the connector plug
is in the 'A' post. There is quite a bit of slack in this so either pull it down or push it up because
the cable routing is into the post about halfway up and out the bottom.
Colin