In order to install an HID bulb kit in a 9th or 10th generation Toyota Corolla (2000 - 2008), you must disable the DRL circuit. This is because the way the DRL circuit operates as it is, you will not be able to have an HID system working on the low beam. The DRL module sends only 5 vdc (Voltage Direct Current) to the OEM low beam bulb, which normally would cause the factory bulb to dim but it will cause an HID bulb to strobe, and possibly damage the ballast since it is not a constant flow of 12 vdc.