I just recently bought a USA train Diesel loco and got a sound car also. Just got a Bridgewerks 15SR last night.
The sound car has two wires with plugs in the front but I don’t know how they connect to the loco. There is also a battery in the sound car but it doesn’t work with just the battery. Apparently those two wire leads have to be connected to the loco but I don’t see any terminals.
Anybody know how to connect power from the loco to the sound car? You’d think there would be a terminal on the back of the loco to powertender or sound car in this instance.