Hello! I'm not familiar with the mod you describe but it sounds wrong to start with.
As far as I know, to mod ACA to PSA you have to remove a resistor and a diode and replace them with links. There are plenty of guides out there, make sure to study more than one to get a understanding of what you are doing. Here is a good one.
http://stinkfoot.se/archives/1019Now, not all boss models are wired the same way, I wouldn't go around soldering stuff based on the wire color. Also, before messing with something it's always a good idea to snap some pics of it before changing anything. That way you can always change it back the way it was.
Some photos of your situation would give us a clue of what you are working on and help you.