Hello out there - I need help concerning wiring up a led reverse light on Walthers proto F7A with factory installed DCC W/sound. It appears, by looking at board and wiring, they used the yellow wires to light leds for the number boards. I would really like to have a reverse light on this loco that would only come on in reverse. How did they get the number board leds to light continously?, if the yellow wires are supposed to be for reverse (as per Soundtraxx diagrams). Thank you for any help, Dave
Basically,the yellow wire is for the rear light but can be programmed differently if desired.Giving CV34 a value of 2 should have it back to normal rear light operation.
If there is an unused function wire available (purple or green), it can be used for the backup light by programming a CV to turn that function on, or you can move the yellow wire to the backup light and use another color for the number boards.
Only the white and yellow wires can be responding to direction changes,so in this case yellow would have to be directed to the rear light and reconfigured.
Then either the green or brown can be used for the number boards or ditch lights or else if configured to do so.
So, since this is a factory installed decoder then it isn't set up like an aftermarket board. If you have the colored wires, then you can certainly follow their normal installation and reconfigure the CVs to get the lights to work as you want. I would move yellow for rear. But if you don't have those wires you may have pads for other functions. So look for F5 of F6 which have soldering pads(small metal squares) next to them. YOu can use one of these pads for your number boards.
Richard