MTH Railking Conrail (NS) ES44AC Diesel Engine #8098 PS 3.0 - 30-20574-1

Stop running it until you fix it!  It's likely the coupler contacts shorting to the axle of the truck, that will kill the board if you keep it up!  It could also be wires chaffed and shorting to the frame around the truck attachment point, but it's not good whatever is causing it!

Would you have idea on how to fix it?  Thanks.

if you don't feel confrontable repairing it yourself get as MTH ASC tech should not be that expensive of a repair but as John said if you keep running it you WILL blow the board and that's not cheap! the problem could be mechanical or electrical won't know until it's checked over!

check out items 13 and 23 and 24

MTH Electric Trains (mthpartsandsales.com)

Alan

@Bo posted:

Would you have idea on how to fix it?  Thanks.

A physical examination is the first step.  See if the insulator on the coupler is out of place and the connections on the coupler coil are contacting the axle on the truck.  If not, then you need to examine the wires from the coupler through the chassis slot to see if they've been damaged and the insulation compromised.

I found the short and taped the exposed wire.  I did maintenance on the engine and did not set the wire correctly when setting the motor in place after greasing the gears.  Now the forward direction light and number board lights do not light up.  Any advice on bringing the lights back on?  Thank you, Bo.