Q: I have a rocker switch that has three prongs (+,-,ground). And then I have a 5 Lazar led that has a molex end to it(with 4 cables 1 yellow, 2 black, and 1 red). And I was wondering if anyone knew how to set this up to where if I flip the switch the light would come on.
A: The 'Molex' power supply connector has 1 Yellow,(12volt), 1 Red,( 5volt), and two Black,( Both are ground wires) Your power supply converts AC electricity, to DC electricity. DC ALWAYS has a Positive,(+), and a Negative,(-) connection. Problem is, I don't know if the Lazar LED setup uses 5 volts, or 12 volts. The Molex connector has four wires, granted. Plus, one is 12 volts, (Yellow), and one is 5 volts,(Red), but just because a four pin Molex connector is used, doesn't mean the Lazar LED setup is using both voltages. It might be one, or the other, with one of them not making a connection to the Lazar setup. Follow me? At any rate, it's time to find out. Do you have a cheap multimeter with OHM's setting? This way you can check the continuity. This method may be considered safe, than simply connecting wires together, and hoping for the best. Set the multimeter to 1K. Touch the leads together to make sure the meter is working. If the 9 volt battery died for the multimeter, you'll be getting nowhere! lol! Touch the Red (Positive) lead to the Yellow wire, of the Molex connector on the Lazar setup. Now touch the Black (Negative) lead of the multimeter to one of the Black wires, in the Molex connector. (On the Lazar setup) Nothing? The needle of the multimeter doesn't move? Then take the Black lead, and touch the other Black wire. Still nothing? Okay, touch the Yellow wire with the Red lead from the multimeter. 0? Take the Black lead and touch the other Black wire. The needle of the OHM meter on the multimeter, should move with one of the combinations. These are the two wires that you'll deal with. If the OHM needle moves, when touching either one of the two Black wires of the Lazar Molex connector, just take your pick of these wires. You need a female socket Molex connector with all four wires coming out. Length of the wires is up to you. See what length of wires you need, to easily connect this Molex connector to your power supply, and to the rocker switch. Remember! The Yellow wire in this Molex connector is a Positive wire. It is a 12 volt Positive wire. This connects to the + on the rocker switch. Or it may be the Red, 5 volt Positive wire you need. The test above tells you which one. The test above also tells you which Black ground wire is the one you want. It connects to the - wire on the rocker switch. The ground connection on the rocker switch, connects to anywhere you want, on the metal frame of the computer case. Edit: I know the above stuff is hard to follow. It's much easier,( I feel), when you have the Molex connector, the multimeter, and the rocker switch in front of you. You are making a circuit. A very simple one. Another simple circuit is connecting a flashlight battery to a flashlight bulb. One wire end connects to the outside shell of the light , and the other end connects to the negative side of the battery. One wire end connects to the middle 'pin' of the light, and to the positive side of the flashlight battery. There's the circuit, or 'circle'. Now cut the positive wire in two pieces. (The wire that goes to the positive side of the battery.) Put the rocker switch in the middle. Doesn't matter which wire, of the two wires, connect to the + on the rocker switch, or the - of the rocker switch.