Failed LED install for Vanderbilt tender

[Priza]

I was trying to replace the bulbs on my Vanderbilt tender with LEDs, I tried to solder them to the to the existing wires going to the bulb. When I tested it with a locomotive on DCC the it did not run and my DCC system only buzzed any ideas how to fix this? if you need better pictures feel free to ask! thank you

[bapguy]

Is this a dcc equiped tender?

[Tenwheeler01]

LEDs are polarity sensitive. A 12v bulb does not care.  I do not see any "+" or "-" markings on the board.  And they did not use the NMRA standard wire colors.

If you have a mutimeter you can check the resistance from PIN 7 (Common) on the 8 pin plug to each of the light connection on the board (you maybe able to visually follow them.)

Make sure the LED is not wired backwards. (if it was you will more then likely need a new LED. Wiring them backwards burns them out.)

On the DCC plug
Pin 7 is Blue common +V
Pin 2 is Yellow rear light - 

LED short lead is Negative  The 1000ohm resistor goes on the negative side.
LED long lead is Positive (Common).

Also I notice that the yellow cap at "C1" is still connected.  Depending on which decoder you are using it is usually recommended to remove or at least cut one of the leads to the cap to disable it. The cap causing speed control issues with most decoders.  (For more info on this, review the TCS decoder install web pages.)