430 2008 USA F430 Tail Light Wire Colours

It was noted on a fellow FChatter's 2008 USA F430 that his tail light wiring wasn't the same as earlier cars. The wire colours are different from expected and there is an extra wire on the inner clusters.

RH inner connector:

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pin 1 - black/blue ??? RH turn is usually blue/black. Do USA cars have the turn lights on the inner clusters?
pin 2 - red/black ... reverse
pin 3 - blue .... ???
pin 4 - black .... ground

At least one of the unknown wires has to be the brake light. My Scud wiring diagrams show pin 1 as being the stop light wire (i.e. a red wire). So what's the (solid) blue wire for?

TIA.