On my 2017 Prius on the rear lights, there is a clear lens with a light bulb with wires going to it, but it doesn't light. So if it isn't used I would like to rewire it for a backup light but I don't know what it is. I Would appreciate anyone that could help me
Here's a video - showing the indicators, tail lights and reversing lamps. I believe the clear lamp below is the BRAKE Light. I couldn't test it as I needed someone to press the brake pedal - though I did look at them in a shop window one night. This photo is from GOOGLE
I had a neighbour press the BRAKE pedal while I went back and looked: 1 = INDICATOR 2 = REVERSING LAMP 4 = BRAKE LAMP
They would never put a phantom bulb in the Prius, for any region. A $0.20 bulb in a million cars is $200,000 wasted. It is almost certainly already the reverse light, which is legally required in America.
The light positions are different in different regions, as far as I know(definitely in the front at least). Both the brake light and reverse light have clear windows here, I can't tell from your picture exactly but it looks like one is colored. The brake light is an LED, whereas the reverse light is a plain old bulb. I suspect if he's driving a USA car and is talking about a clear window with bulb, it must be the reverse light.
My Focus had clear indicator windows - but had yellow bulbs. Check it out - I had a neighbour come over and press the brake pedal - and the CLEAR WINDOW is the BRAKE.
