If your HID bulbs do not light upon installation, the likely explanation is that the stock wiring’s polarity is reversed, relative to the ballast. In other words, the power and ground wires of your vehicle’s stock harness are reversed relative to the ballast. To correct for reverse polarity, please remove the plug from the input socket of the ballast, flip the plug and re-connect it. The HID bulbs should now turn on. If they don’t, you may have a fuse that is blown; if so, please replace the fuse then try the HIDs again.