Help with light wiring for proto 2000 (HO) gp 38-2 with a digitrax 163LO decoder is a free Model Railroad Discussion Forum and photo gallery. We cover all scales and sizes of model railroads. Whether you're a master model railroader or just getting started, you'll find something of interest here.


New Member
I am looking for some help with the wiring of the HO proto 2000 gp 38-2. On the Tony's trains website, there is an issue with the lighted number board causing problems when the decoder is plugged in. One must disconnect the bulbs to the number board for the loco to operate properly on dcc. I got the Digitrax DH163LO decoder which has resistors for the stock bulb for the headlights. I am unable to figure out 2 things.

1. How to best rewire the number boards. I hear one can wire them to a function but if I do that, does the decoder's resistor work when connected to a function or does one have to replace the bulbs with either leds or higher voltage bulbs? The stock bulbs are low voltage. Where is the best place to connect to a function? Which wires go where?

2. the loco has a circuit board which plugs into the decoder, the lights are connected to this board and the question is, can one use this circuit board to wire in the numberboard lights, and if so, in what positions to the wires go? Or is there some other way to reconnect the number boards?

If someone knows the answer to this question, please tell me exactly what pins to hook up the wires to. I find both the instructions for the proto and for the digitrax decoder to leave out needed info. I am new to all the wiring issues for DCC and am not sure I fully understand the wiring very well.

Thanks for your help

Eric, cpmodeler

grande man

Bonafied Grande Nut
Have you seen this on the Digitrax website? Maybe it'll help.

Life-Like GP38-2 locomotives have an additional lamp added for the number boards which, as wired, causes problems on DCC (it does not adversely affect DC operation). Since the bulb is wired to the gray (negative motor) pin and the black (track pickup) pin, your DCC system will see this as a short circuit. Disconnect the bulb from both pins and wire it to one of the function leads on the decoder to solve this problem.


Life-Like Proto 2000 locomotives with number board lights have the number board bulbs wired to their 8-pin DCC plug using pins 4 and 5. This causes no problems with DC operation but causes a path from the rail pickup to the gray motor lead when a decoder is installed resulting in erratic operation and decoder failure.

The DH163L0 uses a current limiter set to control one incandescent bulb on the front (FOF) and one on the rear (FOR) and putting the removed number board bulb on either FOF or FOR will result in two very dim bulbs if they light at all, and putting the number board lights on one of the functions will require a resistor defeating the purpose of using the DH163L0.

Aksel Suarez solved his problem by removing the incandescent lamps and using LEDs. He got good brightness on all lights and number boards without using resistors.

Aksel used the white LEDs from Mouser Electronics (,

Part #604-L7104QWC/D, rated at 3.5Volts and installation involved removing the number board lamp, trimming off the headlight bulbs, and bending and trimming the LED leads to fit in the area provided for the original lamps. He then soldered the 2 LEDs together. After tinning the original wires he soldered the lamp common wire from pin 7 (lamp common) to the positive (longer) side of the LEDs and the return wires from pin 6 and 2 to the negative (shorter) side of the forward and reverse LED bank respectively. He then covered the bare elements and connections with liquid electrical tape to avoid short circuits to the locomotive’s frame, tucked the lamps into position and held them in place with a bit of electrical tape.

The result was a well-lit model using a favored decoder with minimum effort.

BTW, WELCOME to the forum!!!:cool:


New Member
Dear grandy man,

Thanks for your quick reply, I hope I can find pin 7 and 6 and 2. Do the number board lights stay on or do they go out as one changes direction?


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