Do it yourself, change the headlight assembly on your Toyota Sienna, the model produced between the years 1998 and 2003. You will require a 10 mm socket wrench and a Phillips screwdriver. The repair is quite easy, but it might take you more than 20 minutes to do it.
You can start the replacement process by opening the hood of your car, thus giving you access to the headlight you wish to replace. Above it, you will first have to remove the Phillips screw shown in the image below, that holds the parking light assembly. Removing this part is absolutely necessary, because it will give you access to a retainer holding the main headlight.
After you remove that Phillips screw, you can pull out the parking light and unplug the harness behind it. Now, you can go behind the main headlight and unplug the harness powering its light bulb, as seen in the next picture. Next to that harness, you need to remove the 10 mm nut marked with the blue circle.
After that, you will have to move above the lens and remove the 10 mm bolt there. The last retainer is to the side, towards the parking light (see image below) and is a 10 mm nut. Pull the headlight out and then, you can install the replacement. Before you do it, make sure you make a preliminary adjustment on the new lens, by copying the distances from the old one.
So, install back the new lens, secure it with the nuts and bolt and reconnect its harness. In the end, reinstall the parking light also and you’re done. These are the steps you need to follow, if you wish to remove and replace the headlight assembly on your Toyota Sienna, made between the years 1998 and 2003.