any auto parts store: auto zone, pep boys, advanced auto store, etc.
If it is a bulb, yeah, your owners manual should show you how to replace it, but if it an LED group then the only way you are going to get one is from a wrecking yard that has a similar model. Do you understand what I mean by LED?
u can check ebay, autozone or amazon. http://lexusgs.org/
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