Greetings. I had the front turn signal bulb burn out on my 2003 GX recently. I started researching the fix on this board and found that this bulb seems to blow frequently. I also discovered that people had a wide variety of solutions that seemed to be mostly expensive and some difficult. My local Lexus service rep told me that "things have to be removed in order to get to it. It will take about 45 minutes and will cost about $55." I didn't believe him so I spoke to a different service rep at the same dealership. She told me that if you laid on the ground beneath the car you could change the bulb from there. I bought the bulb at Lexus for $12.
Luckily the dork at the parts counter gave me the wrong bulb. Frustrated, I went to my local Schuck's Auto Parts and did some homework. Turns out this is a very common bulb, the 1156A (for Amber) and I got 2 for about $3.50. I swapped the bulb out in about 3 minutes myself in the driveway, on my back, from under the front bumper. Very easy. Needless to say, the $12 bulb is returning to Lexus today.
Anyway, hope this helps others with the burnt bulb issue.
Bill