Disclaimer: I’m not responsible if you break your fans or fry your computer trying to do this mod. If that happens, you’re on your own.
When I was picking a new case for my computer, I was trying to decide between the Corsair 500R and the 600T. One of the things I liked about the 500R was that it had an on/off switch for the fan LEDs, but I liked the 600T more so I picked that. I’ve been wanting to add an LED switch since I bought it, and I just recently decided to do the mod. Unfortunately I didn’t get any pictures while I was doing it but I’ll do my best to describe it. Here’s what I did:
1. Peel back the Corsair sticker on the fan and see which wire going to the LED is the negative. On mine the positive appeared to be a copper wire and negative was aluminum. Cut the negative wire wherever you want, and strip off the insulation on the part of the wire connected to the LED. Repeat for all four LEDs.
2. Cut a piece of wire that goes from the end of one of the LEDs negative wire to the one across from it. Neither of the LEDs this wire is connecting to should be the one next to the fan power cord. Strip the insulation off each end, and cut out a small section in the center. Solder the negative wires to each end of the one you just cut.
3. Cut another piece of wire that goes from the LED opposite from the power cord to the end of the power cord. Strip the insulation at each end, cut out a section of insulation where it will make contact with the wire from step 2 in the middle, and cut out another section next to the end of the LED’s negative wire next to the power cord. Solder both the LED negative wires to that piece you just cut, and make sure the two wires you cut make contact in the middle. You could solder these, but I just taped them together with electrical tape.
Repeat the above for both fans. Here’s a high quality illustration I created using high end photo editing software (Microsoft Paint).
For the switch, I pulled one out of some sort of broken electric device. I already had this wired into an LED strip, so I just connected the long wire from step 3 to what I already had. Whatever you decide to connect your switch to, make sure it’s a negative wire. I’d recommend doing it the way I did it; that way you can shut off all the lights in your case with one switch. If you don’t have any other lighting in your computer, then you’ll have to get a molex connector and solder the wires from step 3 to one side of the switch, and then run another wire from the other end of the switch to the negative on the molex connector.
I have my switch under the black cover on the top.