Take a loot at the Massoth website. There's a "discontinued Items" under the products tab.
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www.massoth.de]
The sound unit is an aftermarket install so the colors won't necessarily match LGB.
My guess is the gr/wh/br triplex is power and hall trigger coming back from the engine portion and the rd/bk/wh on the left is the connection to the reed switched mounted on a tender truck to trigger wayside sounds.
Some of the dealers have paperwork on their websites if you want to go all the way
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www.onlytrains.com]