I have a 2002 rx300. went crazy with this a few months ago. I was told by one dealer you need to take off half of the rear cargo panels on the drives side find a conncetor. I did this found a connector that was not the right one.
The bad news you need the little wire harness kit from Lexus $200.00. Comes with a blue relay switch with you do not need, and a wire harness. after getting the kit & wire harness no one at the dealer could tell me where this connector plugs in. They sent me to another dealer who installs hitchs
and said they could tell me? So after driving all day went to the third dealer and begged them to
have someone show me where the connector is for the wire harness! presto!
right under the back of the car there is a black plastic box. remove the four 10mm bolts take off the
box there it is! the connector!!!! just plugin the wire harness, put the cover back on.
One more thing! there is a fuse that has to be put in under the hood fuse box, there is a empty
spot that says trailer lights.! Your done takes about 15mins. after days of calling and running
around!