I have a couple of El Cheapo internal disk caddies and I wanted to install one in a Dell PC. This caddy had no power switch or LEDS. It's a kind hybrid oddity in that it has a SATA data connector and a Molex power connector. I started by popping out the flimsy lock mechanism and inserting a double pole switch in it's place. Cut the Molex Red/Yellow leads and fed the 5V/12V power into the respective poles of the switch, then the output contacts of the switch to the caddy side red/yellow wires. Since there was no power indicator on the caddy, I also fed 5 Volts from the switch output to a LED/resistor combination (power return was to the 5V ground (black) wire). All connections were soldered and heat shrinked. The wiring I used was 24 gauge solid strand (3 amp?). Since I'm only using a small SSD in the caddy, I thought that would suffice. Drilled a 3/16 hole above the switch and popped the LED into it -it's bright but the case sits on the floor so there's no blinding glare. Modified another one (it had separate power and data LEDs, but no switch). Used stranded wire from a defunct power supply in this instance: I use it for HDD as well SSD.