I have a 2012 Lexus Rx350 with 94,000 miles. The car no longer beeps or chimes when locking the doors. Anyone had any experience with the buzzer going bad?

 

Learn to search and you will find the answer to almost any questions on this forum as these cars are aging and most have been asked already as they slowly fall apart.

See this as you may have somehow turned it off: The PDF in the link is dead, but it apparently refers to section 06-02 of the owners manual. If you don't have one, you can see it at the Lexus Drivers Site.
https://www.lexus.com/My-Lexus/account/create-account

​​​​​​https://www.clublexus.com/forums/rx-...zer-sound.html

Or it may be broken: https://www.clublexus.com/forums/rx-...t-working.html

​​​​​​https://www.clublexus.com/forums/rx-...placement.html

​​​​​​https://www.clublexus.com/forums/rx-...placement.html