How to install dcc decoder in gp40

[ducky]

Could anyone help as I am new to doing this.  I have a EMD GP40 and have purchased a decoder board to make it run on dcc, it was supplied from Bachman but did not come with any directions as to where each wire is connected too, if you can help or advise me where I can get a diagram of how to connect it I would be very appreciative.
Many thanks Graham

[Rangerover1944]

There are so many versions of that loco, is it older or a newer version. Is it HO or N scale. Does it have a split frame. Does it have a light board. Does it have an 8 or 9 pin plug already installed from the factory.

I don't understand why it has no instructions, I've never received a decoder without the installation instructions included.

Just in simple language the red and black wires are for the electrical pickups from the wheels. The orange and gray wires go to the motor brush's. The white wire goes to the front headlight along with a resistor, usually 1k ohm resistor. The blue wire (common wire) goes to both front and rear lights. The yellow wire again usually with a 1k ohm resistor goes to the rear light.

If you have more wires than that, it's a four or 6 function decoder. The other wires are for such things as ditch lights, mars light, rear strobe, rear tail lights, flickering fire box for steam engines, cab and or to light up road numbers, etc.

If you need pics of the install, again we need to know more detail. Jim