The way I finally visualized it is like check valves. The only let the juice flow one way. So you nip the two wires going into the indicator bulb. You solder one end (forget which off hand) of the diode to each wire coming from the harness. Then you join the other end of the diodes TOGETHER and to one of the leads on the bulb. Then you send the other bulb lead to ground. On page one of this thread there's a good diagram. If I ever get around to it I'll snap pics along the way.
