Where is the Back-Up Switch Assembly located? on 2004 Toyota RAV4

I was told by my dealership that I needed to replace the back-up switch assembly on my 2004 (manual) RAV4. I have the part (it looks like a spark plug) and appears easy enough to install, but I have no idea where it is located on the car. Any idea?

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1 answer 1 comment
Red/black and a Red/blue wire attach to the switch, (10 amp fuse marked gauge protects the circuit). My illustration shows it on top of the transmission.
Thank you!!