Molex volt per pin question

[BlindBartimaeus]

Where do I get a diagram or can someone tell me what the voltage rails on a typical molex connection. I basically want to mod one so I can run my 120 mm fan at 5 volts.

Thanks

 

[BlindBartimaeus]

http://www.dslwebserver.com/main/fr_index.html?/main/5-7-adapter.html

for those who are curious

 

[lenjack]

On the typical 4 pin connector...

Yellow=12 volts
Red=5 volts
Black=0 volts (ground)

The 2 blacks can be considered the same.