I hope. I also found that the battery is supposed to be grounded to the frame. Mine was only grounded to the forward block hook.Good find. That could certainly explain your problems!
I had some West Marine 1 AWG wire left over from my M12000 install on my 80 series so I made new + & - battery cables too. I will use a smaller gauge to ground the battery to the block and body aswell. I also replaced the starter frame ground with a 4AWG gauge bonding strap from @ToyotaMatt. I will add his other frame and body bonding straps too.