Ray
I had the same on mine not long ago. This article helped:
http://www.clublexus.com/forums/ls430/4451...rt-numbers.html
although remember that this is for a left-hand drive car so when they refer to drivers side, it's the other way around.
FWIW, I sourced a Bosch Universal part (from the US, as it happens) and got the whole job done for £159 which is a lot cheaper than a main dealer will charge you.
Chris