If the light is the same as my 2001.. you have 3 silver clips 1 in the middle and two small one on the left and right. The housing pops out below the red reflecter. You have to press in the left and right tabs and pull down you may need to use a small srewdriver to push the clips in on the sides. The middle clip comes out easy.
Ihave the same problem but Lexus told me the code is P1130 A/F sensor.. the lights stayed off for about a month and now they came back on. I have to bring it back to the dealer.