Odd Event caused by tether?

I would check for any loose wires on the tether connector. I has this happen with a PS3 wire drawbar style connector where the attach wire broke.

What do you mean brightly?  Like full voltage bright? Or normal bright?  I assume this is a J with the MUX board not a Bantam on?  Could be a loose connection in the engine and certainly a loose tether connection or  pending bad wire in the harness.   If MUX model the engine lights and markers are powered from the mux board in the engine with a signal wire from tender that tells it what to do.  Loose or damaged signal wire, might cause what you see.  G

George, thanks for the response. The engine is 20-3132-1 if that helps. The cab light flickered brightly, like at full voltage. At first I thought there might be a board problem but now I'm hoping it was just a loose tether connection. However, my experience with bad tether connections is the engine stops or won't move. I guess these things are all different and I'm looking for support here that the tether could cause what I experienced. So far the engine is working fine.

GHD posted:

George, thanks for the response. The engine is 20-3132-1 if that helps. The cab light flickered brightly, like at full voltage. At first I thought there might be a board problem but now I'm hoping it was just a loose tether connection. However, my experience with bad tether connections is the engine stops or won't move. I guess these things are all different and I'm looking for support here that the tether could cause what I experienced. So far the engine is working fine.

Usually a bad solder joint at the PCB is outside pins, so motor leads and such.  Real bad can be multiple pins.  Tethers can have any wire break, though they seem to be ground, 5V, tach, and smoke wires.  If it is running fine could have just been a loose connection.  Changing tethers should be easy, the universal BC-0000217 plug in type if needed.  G