Things You'll Need
Lock cylinder with key
The two primary components in a Toyota truck's ignition system are the actual ignition switch and the lock cylinder, which work with the ignition key. On most current models of the Tundra and Sequoia, you won't need to completely disassemble the entire steering panel to access the switch and cylinder. Keep in mind that the exact procedure can vary depending on the year and model of your Toyota truck.
Disconnect the truck battery's negative cable by loosening the cable's clamp nut and detaching the cable from the battery post. Set the cable aside somewhere where it can't accidentally touch the battery terminal.
Remove the under-dash panel on the left side of the truck by removing its four retaining screws and pulling it off. Detach the hood release cable by lifting the lever, removing the screws and disengaging the cable from the lever handle.
Remove the air duct that is below the steering column to access the ignition switch. Unplug the electrical connectors at the rear of the switch, remove the mounting screws with a screwdriver and detach the switch from the lock cylinder housing.
Detach the illumination ring by pulling out the plastic pin on the side. Turn the lock cylinder into the Accessory position with the key and insert a small screwdriver into the hole at the bottom of the ignition switch casting. Press the release bottom with this screwdriver as you pull the lock cylinder straight out.
Insert the replacement lock cylinder with its own key into the ignition switch casing. Make sure you insert it so the cylinder is in the Accessory position. Replace the illumination ring with its pin.
Mount the replacement ignition switch on the housing with its mounting screws and connect it to the electrical connectors.
Re-install all other components--the air duct, under-dash panel and battery cable--in the reverse order of removal.
Disconnecting the battery cable will cause the ECM to lose information stored in its memory. It will take some time for the computer to re-learn the information once you re-connect the battery.