The three leads coming from the front-panel on my Cubitek MiniTank case (ON/OFF, RESET, HDD LED) have two black wires each. On each of these leads, one of the wires is marked with a little arrow on the connector. What is the convention? Does the arrow indicate ground wire and the negative? Or the power-wire and the positive?
Even if there is a convention, it doens't mean that the case manufacturers followed it. You should check the manual for the case.
For example, black should always be ground/negative. In typical wiring, you have red/white = positive, black = ground/negative, green/bare copper = ground. If there is no green, then black is ground. This is a basic convention that any electrician should follow. Since you have two black wires, the case designers were idiots. Did you check to see if one of the wires is black with a stripe? If so, that wire would be positive, and the solid black wire would be ground. If that isn't the case, then I'd guess that the black wire with the arrow is positive, and the one without is ground.
The "manual" for the Cubitek Mini Tank is a single one-sided oversized piece of paper in multiple languages, folded like a city map.
The section on front i/o port installation covers USB (it says 2.0 but the USB cables say 3.0) and HD Audio only. There is nothing about the POWER ON/OFF, RESET, or HD LED wiring.
The wires are not multicolored or black and white, and I don't see any stripe, but there is some minuscule lettering on the wire that is marked with the triangle on the connector. The opposite wire has no printing on it.
download the entire manual for the board from the manufacturers website.
It will show the connections with all the details.
The ASUS manual is fairly clear. It's distinguishing which wires are which on the front-panel leads (power, reset, hd_led) that is the problem. I know which pairs of pins on the m/b go with each of those three leads from the front-panel, just not how to orient the two-pin connector on the pair of pins.