The year 2004 marked a difference in the Toyota Sienna, as it was made larger to compare with other minivans in the automotive market. The 2004 Toyota Sienna featured two-wheel drive on the CE and XLE models and all-wheel drive on the XLE model. The base 2004 Sienna came equipped with a 3.3-liter, 230-horsepower V-6. The headlight assemblies were also larger on the 2004 Sienna, versus the 2003 and earlier models. The 2004 Toyota Sienna headlight assemblies were a one-piece design, as compared to the previous models that had a separate headlight and turn signal light assembly on both front corners.
Raise the hood on the Sienna. Disconnect the negative battery cable with a ratchet and socket.
Remove the headlight mounting bolts from the radiator core support, located at the end of the mounting tabs. Use a ratchet and socket or a Phillips screwdriver to remove the bolts. Pull the headlight assembly out over the front bumper.
Remove the rubber boots that cover the backside of the headlights. Remove the high and low beam headlight sockets from the headlight assembly, by turning them counterclockwise. Remove each bulb from its socket by hand and discard the old bulbs. Remove the turn signal socket from the corner of the assembly in the same manner, turning it counterclockwise. Remove the bulb from the socket by hand and then throw it away.
Remove the old headlight assembly completely from the Sienna. Set the new headlight assembly onto the front bumper. Wrap each new light bulb in a paper towel and do not touch the lenses with your bare hands. Install fresh light bulbs into all of the bulb sockets. Install the new high beam headlight bulb and socket in the hole nearest the grille and turn the socket clockwise to lock it in place. Install the turn signal bulb in the same fashion on the outer corner of the assembly. Install the low beam bulb into the center of the assembly.
Install the covers over the rear of the headlight bulbs. Install the headlamp assembly back into the front grille area of the Sienna. Install the headlight mounting bolts into the radiator core support and tighten the bolts snug.
Repeat steps 2 through 5 if you are replacing the headlight assembly on the second side of the Sienna. Turn the key to the "II" or accessories position in the ignition. Use the different settings on the headlight switch to check all of the front lights. Turn the key off and turn the headlight switch off when you are finished.
