This installation of TCS T4X Decoder is for HO Scale Walthers Trainline EMD F40 PH and was performed by A.G.
Here is a picture of the locomotive with its shell on prior to the decoder installation.
Remove four Phillips screws on both side of the locomotive as marked in pictures above, and gently remove the shell.
Unsolder all wires that are connected to the original light board as shown in the picture above.
Use the harness that comes with TCS T4X decoder to perform all connections and make sure you isolate all solder points. We used shrink wrap tubing in this example.
Here is a picture of "almost finished" installation. This engine comes with forward, reverse and two strobe lights which is the reason 4 function decoder was used (T4X). All bulbs (4) are 12V. bulbs so no resistors to decrease the voltage are needed. Bulbs used in this locomotive are not "electrically directional" so you can pick one end as either positive or negative. One wire that comes from the forward light was soldered to the white wire of the decoder's harness, and the other was left alone for now. The reverse light was hooked-up in similar way using yellow wire that comes from the decoder's harness. The two strobe lights that are placed on locomotive's roof, were connected together to the green wire of the decoder's harness. The blue wire that comes from the decoder's harness is the common, positive wire for all lights so all those bulbs wires that were left alone earlier need to be connected to the blue wire of the decoder's harness. We pretty much followed the wiring diagram that comes with the decoder.The purple wire of the decoder's harness is left unused as we only used 3 function. As mentioned earlier, make sure you isolate all wires' solder points with either electrical or Kapton tape.
All wires were neatly placed under the light board and some electrical tape was used to keep them organized.
Here is a picture of the installation's final step. After all the assembly was completed, value of 4 was placed into CV51 so that the strobe lights will pulse when the Locomotive runs forward.