What is this wire? Why is it disconnected?

Looks like an "add-on" which someone has only partly removed, my first question would be what's at the other end? Do you have access to, and know how to use a multi-meter? …if you fancy yourself as a "Sherlock Holmes" Good luck! - Wil BTW Welcome to PriusChat! I have a niece living in Auckland, and when I visited NZ back in 1991, I was amazed to see all the cars I loved when I was growing up in the UK in the 60s and 70s (Minis, Lotus-Sevens and many others) - a bit like going to Cuba and seeing all the old cars from the USA.

 

Yeah, looks aftermarket. Both of those red wires. If I remember what my 2008 looked like back there, all cables were nicely wrapped and no stragglers. I also remember on mine there was a fused cover that went over the positive cable clamp, which isn't on a 2005 or is missing.

 

welcome! nah, they have to cover anything under warranty. how many miles on her?

 

amazing that a dealer would sell a car with that many k, and give you a warranty. wouldn't happen here.

 

I see something else odd in the picture, the location of the 12V battery vent line. It should be plugged into the port on the left side of the battery (left, in the picture). Or maybe this battery has dual ports, one on either side, with one in use (on the right side) and the other plugged. I heard there were batteries that had that option.

 

It looks rather like an add on for a taxi radio and accessories, even more so with that high mileage. My own Prius had a similar (though tidier) attachment, though mine included fuses.

Check the floor and seat on the passenger side rear. Are they worn or brand new?

 

I have edited your picture to add a couple of arrows. The purple arrow in the lower left of the image points to where the vent hose exits the trunk to the exterior of the car. If you follow that rubber hose to the right in the image it will meet up with a solid plastic right-angle piece that plugs into a port on the side of the battery. This piece is keyed to retain it in the port and can be removed by carefully turning it (don't remember which way) and removing it. Your battery might have a vent port on either side, which I remember reading was available on batteries sold in non-U.S. markets. If your vent line is plugged in on the right side of the battery and there is no port on the left side then don't worry about it. There is a white arrow pointing to approximately where a left side port might be on the top left side of the battery.

 

Tagging on to your other thread about the battery, that's definitely not the right battery. The vent is there for a reason--hydrogen. You don't want that in an enclosed compartment with a possible spark source!

 

...could it be wiring for an inverter for elec power out? Many of us hook up inverters to the batt for power to the home during emergencies

 

Yes, and I'll put it in more graphic terms--a hydrogen explosion, spraying battery acid, lead, and case fragments through the passenger compartment.