Use these harnesses if your car has Daytime Running Lights (DRL) and you are looking to avoid having them shut off at the dealer. You can also use these harnesses to potentially solve flickering, bulb out messages, or HID set ups where you know the kit works but still does not light up or lights up and then shuts off immediately. Most newer cars require this as installing HIDs without may be unsuccessful. Please note you may also need to buy our computer bulb out warning harness in conjunction with the battery harness to prevent problems such as bulb out warnings and flickering. If you have any questions please don't hesitate to email us at sales@sharphid.com.