I do not own the Lexus rx300. But it is in the family. I just put a new motor in it for them but the kids worked on it before me so there is a few things to can't remember where they went. Being said.. Where do these go?

 

While we wait for a member to respond. you can try to look at the part and see if it has the part number stamped on it. The google the part number and hopefully you will get to an image.

I sincerely wish that to instal them you don't have to undo lot of stuff. I know the feeling [forgot to slide the plug cover on the wire before attaching the wire on to the prongs]

Salim

 

The black thing on the right is for tightening you alternator/ belt