I want to confirm a few things in you message.
You mention a wrong code. Is this for the light or when I follow the reset procedure on page 13 step #8 to enter the #8 as a code. I want to make sure I am doing correctly the reset.
Basically, it’s both. The codes I gave you (5 or 6) are for a reset/restore of your locomotive’s electronics. This also sets the function of the light on top of the cab. The 8 code printed in the manual is wrong, as that’s for a diesel with smoke. So follow the procedure on Page 13 but enter a 5 or 6 (your preference) instead of the 8.
if that doesn’t improve the situation, try operating the loco in conventional mode (unplug your TMCC base) to see what happens.
i don’t believe an unusual R2LC is found in that loco, so it wouldn’t be a big deal if that needs replacing. Same thing with the ACDR. The motherboard, on the other hand, is a unique animal to handle the missile firing, but that shouldn’t have anything to do with direction control.