I've seen this topic come up a few times so thought I'd mention that the May issue of Classic Motorsports (just arrived in my mailbox) has an article about adding circuits for a set of air horns and a set of driving lights in a Midget. Obviously a direct carry over to a Mini....

I already picked up one thing I didn't know b4 and had a 'duh' moment:

"....and those of you that speak Lucas know that the colors all mean something: White is switched (on when the key is on), unfused; green is switched, fused; brown is unswitched (always on), unfused; and purple is unswitched, fused."

As many times as I traced wires for a circuit I never thought about the color always being the same type of circuit....

The basics of the article, determining the new load and determining the need for a relay applies to classics and new....

 

i think it would only make sense for them to be the same color...

 

I'm colour-blind. Aren't all the wires the same colour?

 

Yes, in retrospect it does for an older car. Hence my duh moment. But how many wire colors are used in a MINI vs a Mini? Not a lot of help there unless there's another part I'm missing. There you have multi-color wires just to be able to find them in a bundle.....