I also have a 2001 gs300, and almost everytime it rains my lights stay on by themselves, the locks wont work sometimes, the light on the radio blinks with the turn signals, it seems to run in some kind of limp mode almost no power, different warning lights come up. Anyone have a clue. I called a few dealers and the best answer that i got was from someone at Sewell Lexus in Fort Worth saying i might have a windshield leak letting water get to the connectors in the kick panels. Anyone else have any suggestions?

The leak sounds about right, getting water on connections causes all kinds of fun problems.

get a hose and spray areas of windshield one section at a time and check for problem. You will then find the source.

u do indeed have a leak of sorts OP also next time OP please try searching.....using simple keywords such as "windshield leaking" i found these (i knew of them though as one is my thread)

https://www.clublexus.com/forums/gs-...ible-leak.html
https://www.clublexus.com/forums/gs-...help-asap.html

thanks guys, i really appreciate it.