I’m doing my first install and have it all hooked up ready to try except the lights, firebox, etc. I’ve looked at the Bachmann manuals on line, which are basically diagrams, and can’t see anything that tells whether the LED’s are 5 volt or not so I don’t know if I need to chase down a resistor.
I’ve always used resistors. Not knowing the specs of the Bachmann LEDs, I would start fairly large, like 1K then reduce that if not bright enough, but I never go below 220 ohm.
The firebox flicker is usually done with a board that you need to feed with the +V line on the LM (battery voltage less a little system loss).
Don’t forget that RP lighting outputs are grounds.
Probably don’t need to say this , but make absolutely sure those wires are tinned and nothing sticking out when you plug them in to the module, i zapped my first one and had to send it back to get the circuit breaker reset. Happy wiring !