Sean Clark, from mp3Car, shows us how the various components in the vehicle are wired. Getting power cables through the firewall is one of the more difficult aspects of any install. In this case, drilling through the firewall of the Altima in the wheel well proves to be the best option. Be sure to use plenty of fire-retardant adhesive on these holes once the wires are fed through. Running the power cables to the trunk can be done along the sill of the driver door. Use care when prying the panel loose. A trim removal tool is recommended to prevent scratching of your OEM parts. The backup camera switching wire and accessory turn on wire are also run along the driver door sill. Wires that aren't associated with powering any device are run along the passenger side sill to prevent interference. These include the front speaker wires, an HDMI video cable, a USB touch cable, a USB iPhone cable, a USB OBD-II cable, a USB cable for an aux input, and a microphone 3.5mm audio cable.