My flashers stopped working and I'm told it might need a new flasher relay. I purchased the LM449 but have no idea where it goes...

 

Not sure about the RX but on my Avalon and many other T/L cars, the flasher is high up under the dash, close to the steering column. It is hard to spot and even harder, almost impossible, to grab onto and remove/replace. I did it but I am a little guy. Removed emergency brake for more room although could have done it without that step. Make sure it is your flasher. Do your emergency flashers work? Many times the turn signal contact wears. Very easy DIY repair if you can solder. Lots of how-to videos on the net.