Wiring diagram for entry level Lionel GP-7 Lionel # 6-28857 part of Alaska freight set # 6-31976

@Ireland,

I found this generic diagram, in the Lionel Supplement 45 Parts List and Pictorial Diagrams:

It covers both diesels with Conventional Control / TrainSounds, and those upgraded to TMCC / RailSounds, on one diagram so it's a little busy, and you'll have to ignore the TMCC / RailSounds circuit boards if your unit doesn't have TMCC or RailSounds.

Also, make sure that your unit has the same motherboard as pictured before proceeding.

Remember also that the wire colors may not match your unit, so everything will have to be traced wire by wire.

Hopefully it will help -- good luck!

Mike

Mike. thank you.  Will take a look at the engine tomorrow with the young lads and your diagram in hand. 

I really don't think that is the schematic for you.  Your Alaska was a very entry level locomotive.  The parts breakdown is on the link below.  You only have 2 boards inside.  One for direction control and one for sound.  That's it.  The train set was not advertised with "directional" lighting.  I'm thinking there is none and the lights come on with the track power.  You might be chasing a ghost.  You should have sound though as long as the switch is in the correct position.

https://www.lionelsupport.com/...32-8543-d08238b7dda7

Steims, your link is indeed to the engine in question.  It is the entry level diesel.  Will play with the wires tomorrow and see if we get sound.  

The engine is running with both motors working and lights are on.  Thanks