Backup light failure

Secondary fuse panel is in the drivers footwell. Easiest way to find it is to lay down on your back and look up. It's a little to the left of brake pedal(left side when you're sitting in the seat, on the right side when you're laying down looking up). It's covered by a panel with the fuse diagram that's very roughly 1.5" by 6". Slightly translucent white if I recall correctly. I think it uses the tiniest fuses on the market, so have fun. I think I bought a fuse kit with the tiny fuse puller because the puller in the engine fuse box was too big. But I could be wrong about that; it's been a year since the last time I had to get down there.

 

I've got a 2024 Prime and there is no physical replaceable fuse(s) for the back-up lights in either the engine bay fuse panel or inside the vehicle above the driver's footwell. In other previous Toyota models you likely would have found a fuse labeled "BKUP LP".

Seems Toyota in the 5th Gen now uses some electronic "BKUP LP" relay or device of some kind within the whole sphere of the Power Distribution Box Assembly to send power to the back-up (reverse) lights when all the ECU computers involved in shifting and what not do their thing to fire up your backup camera and illuminate your shifter and MID display with the reverse gear. Never looked myself until tonight but I had assumed these back-up lights were up high on the light bar but they are in fact down low on the far left and right of the bumper at the level of the license plate.

Here's my view of the fuse panel above the driver's footwell for your reference:

 

Ah, my memory was reversed on the colors. I thought the housing was black and the cover was white, but it's the other way around. My bad.

And LRO is correct that there's not a separate fuse for the backup lights. If they're not coming on, you've likely got either a wiring issue or the relay in the power distribution box assembly is faulty.

Have you done any mods at all to the electrical system?