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Discussion Starter · #1 ·
i need help, i have wired up the above for led to work with dcc function. but no joy, i have wired the resistor form the blue to the red and then the black and nothing, loco works BUT. not the light. i seen it somewhere that if it's a grain of rice or grain of wheat you don't need a resistor. hence the question. is it a led or one of the other.

thanks for any replies

john
 

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What do you mean "wired the resistor form the blue to the red and then the black"?

The light should be connected to a function output. The Blue is the common return from all the functions. The light should be wired up to the yellow/blue, white/blue or purple/blue.

The front light is usually white/blue and the real light (if you have one) is usually yellow/blue.

Front and back lights are turned on and off by F0 (Function zero).
 

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Discussion Starter · #3 ·
hi doug,

sorry, the red & black wires on the loco, to the common blue via resistor. and white function wire

john
 

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Dear John,

There are plenty of articles on the web describing this type of wiring. See Electric Nose for some good examples with photos. The important text is :-

"The core principle of lighting under DCC is that the blue wire (actually called the common positive) is connected to a resistor that is in turn connected to the 'anode' (positive side) of the LED. The other terminal of the LED, (the 'cathode' or negative side,) is then connected to the function wire of your choice to complete the circuit. In this photo the white wire has been used, which is the first function and most often used for headlights. Pressing the matching function button on your DCC controller will switch this function (and hence the light) on and off. "

From your post, it sounds like you have connected the LED to the motor wires (red and black, if you are following the DCC standard). which does not sound like the above description.
 
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