Be careful about taking the Lexus fuse listings in the owner's manual as a sure diagnostic; often they don't tell the whole story. I have a 1995 SC400 for which the lighter was out and found fuse 14 to be open. It's a 15 amp (blue) located on the driver's kick panel (check the manual diagram for fuse locations). I've discovered that in spite of the assignments in the manual several fuses may affect various other components as well. I got a clue about this by reading this forum - it may be a good investment in time to simply check every fuse in the panel whether or not the book says it has any connection to the problem. P.S.: There's a factory fuse puller stashed inside the lid of the large under hood fuse box (if someone hasn't removed it previously) that comes in very handy for pulling and checking the fuses while standing on your head in the floor board.
BTW, one reason the lighter fuse blows often is that the lighter faces upward so any object such as a penny or paperclip that falls into the ligher socket while the lighter is out can cause a direct short that draws heavy current for extended periods. The fuse is there to protect against that heavy current draw scenario.
Thanks, I will check all the fuses when she is home again.