While not a diagram, a couple of years back there were two or three You-Tube videos on installing decoders in those engines. They may still be there.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
Hroth7,
I spent a liitle time searching and I can't even find that decoder. I would only be guessing, without seeing it. Lights/Speaker?
My suggestion: Give Walthers CS Tech a call, not e-mail, faster response:
http://www.walthers.com/exec/mailcustserv
Frank
Greetings! Does anyone have a wiring diagram for a QSI 187-2v7-42-2 sound decoder? This is the one that comes factory installed on the Walthers SW8/900/9/1200 switchers. If anyone can tell me where the wires from the two plugs go it would be greatly appreciated. Thanks.