Dan Padova posted:Thanks. So basically a DPDT momentary pushbutton switch will do the trick ?
You could use two of these, or two DPST, one for the uncouple function(two hot rails) & one for the unload function(one hot rail / one ground rail) which basically duplicates the original controller. Pushing both buttons at once will, like the original controller, cause a short circuit.
If you use one switch, then you need a DPDT (on)-off-(on) switch - which is a momentary, center off. This precludes the use of a button, so a toggle or slide is what you want to look for. Here is one example from All Electronics. Since both positions can't be used at the same time, a short can't happen.
