The Infiniti QX4 was first introduced in 1997 as a replacement for the Nissan Pathfinder. The QX4 was produced by Nissan until 2003, at which point it was replaced by the QX56. The 2001-2003 models of the QX4 use high-intensity xenon headlamps, which contain a bulb and a ballast. Removal of both requires the use of a socket wrench, as well as a Phillips screwdriver. The older models use a traditional headlamp assembly.
Open the QX4 hood, and unhook the black negative terminal from the battery, using a socket wrench.
Uninstall the three screws, holding the QX4 headlamp assembly in place. Unhook the electrical plug connector from the rear of the assembly.
Pull the QX4 assembly out of the vehicle. Secure the new assembly in the engine compartment, lining up the grooves with the slots for the headlamp assembly.
Attach the electrical plug connector to the rear of the new headlamp assembly, and secure it by reinstalling the three screws.
Reconnect the black negative terminal to the battery, and close the hood.
Turn the QX4 engine off, and open the hood. Disconnect the black negative terminal from the battery. If replacing the left-hand side headlamp assembly, pull the battery out of the engine compartment.
Unscrew the black plastic lid behind the headlight. Remove the electrical plug connector by turning it to the left.
Unhook the two metal braces that hold the bulb and ballast in place. Pull both out, and install the replacement bulb and ballast, making sure to not touch the glass portion of the new bulb. Pay attention to how the two divots on the bulb line up with the slots in the engine compartment.
Reinstall the two metal braces. Reattach the electrical plug connector, and screw the black plastic lid back on.
Place the battery back into the QX4, if it was removed. Reattach the black negative terminal to the battery, and close the hood.
