I can speak for the Lexus '99 ES300. The instructions already provided for the '96 are very much on the mark. However, in the '99, there are only two 10mm bolts instead of three, and the turn signal assembly is fastened to the main headlighy assembly by a single phillips-head screw. After removing the splash guard, the two bolts, and the phillips-head screw, the turn signal can be CAREFULLY loosened and worked free from the fender, without fully removing the headlights. And unlike the '96, there is no clip to worry about, and no circuit board.
FOR 99' ES300 MODELS: You do not have to do the things mentioned above. The process is much easier and simpler. No need to even open the hood. All you have to do is pull the whole turn signal assembly forward. NOTE: It is important that you do NOT pull it sideways or even at an angle for it might break the plastic clip. There is only one clip holding the assembly from the frame. To start, use a screw driver or similar and insert it in the farthest part of the signal light assembly from the front. Pry gently to move the assembly forward about an inch or two to completely unlatch the plastic clip that is holding it in place. This clip is located in the middle of the assembly. Then remove the assembly still attached by the wires. Twist the lamp holder out of it's socket to replace the busted light.