Need a 1200-1500rpm 6CM Fan

[peterb]

Just use the red and black connectors. It isn't clear what the yellow lead is for in this application, but most likely to be tach output so that suitable hardware/software can determine the fan's speed. But leaving it disconnected doesn't matter.

[kalniel]

How would I wire it though? In my light I can only connect a red and black wire. No where possible for a third

You connect the resistor in series on the red cable. This reduces the voltage going to the fan so it spins slower.

The third cable (green, or yellow usually) is just a sensor out so that motherboards can read the reported fan rpm. You only need the red and black.