I've tried it, It didn't work for me the Led's went really dimm and they flashed too...... I've ran the Led's off a seperate molex. Just snip the red wire,make sure you snip the right 1. and run it to a molex, you can leave the black 1 where it is...I ran mine to a switch so I can switch the LED's off if I want..........
Well I've ran 4 led'ed fans of the same molex with no problem......... If your are not sure about anything, just ask..........