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Make sure you have a stereo jack, not a mono (stereo has three solder points). A stereo jack is configured to accept the Tip/Ring/Sleeve (TRS) male plug from the iPod, etc. TRS carries Left +, Right +, and ground in that order. This should correspond to solder points labeled 1, 2, 3 on the jack. If you are using a 4 wire cable from the 4PDT switch: Left + to 1, Right + to 2, Left - and Right - both to 3.
Indy, if you are still monitoring this thread, here ya' go: