Just a quick video showing how easy it is to replace a headlight bulb on a 2000-2006 Toyota Tundra. This is on a 2004 Tundra DoubleCab.
The replacement bulbs used were SYLVANIA 9003/H4 SilverStar Ultra.

Changing the bulbs was very easy, as you will see in the video, and can be done without the use of any tools.  First, you will need to pull off the rubber headlight boot at the back of the headlight assembly.  In the middle or center of the rubber boot is the electrical connector that plugs into the headlight bulb.  Most of the time, the connector will come off when you pull back the rubber boot, but if it doesn’t come off, you can carefully disconnect it once the rubber boot is pulled back out of the way.

With the electrical connector removed, you will see that there is just a metal wire or spring clip that is holding the bulb in place.  The video shows a close-up of how to release this spring clip to access the bulb.  The old bulb will almost fall out into your hands once it is removed.

Installing the new bulb is as easy as taking out the old one, but please be very careful not to touch the new bulb, as any oils or dirt can damage or shorten the bulb’s life.  I usually wear disposable gloves to make sure my fingers don’t accidentally touch the bulb.

Make sure that the tabs on the bulb line up with the slots on the headlight housing and push the spring clip back into place to hold the bulb in place.   Finally, you can plug in the electrical connector and at the same time push the rubber boot back in place.  Just remember to turn on the headlights to make sure they are working properly, and you are done!

Below is the link to the bulbs I used: