So I went ahead and carried out the hybrid battery fan cleaning/maintenance. To my surprise the fan was spotless? Even though the seat vent had no inner/outer filter at all. I purchased an outer clip on filter anyway just as a precaution. I came across a wire (fused) but connected to absolutely nothing under the back seats. Anyone have any clue what it could be for/leading to? Was totally exposed to my surprise, so made it safe for now. Not sure if it's factory or previous owners own addition. I also saw a small hose next to the 12V battery, wonder what that is for? Is it meant to hang down next to the battery like that? Additionally a wire leading into a dead end brown terminal thingy? Just looked intriguing so thought I'd ask what it is for? Thanks!
The small hose shouldn't just be hanging down from the battery, the bottom end should be going out through a grommet in the floor. If the battery ever vents, the sulfuric acid, hydrogen, or hydrogen sulfide goes out of the car instead of into the cabin. The wire under the back seat looks like a previous owner had some kind of thing they wanted to wire in. I can't ID the brown thingy off the top of my head, but the wiring diagram probably can: Toyota Service Information and Where To Find It | PriusChat
One end of the hose is in the grommet, other end is hanging down next to the battery. Is that the correct setup? Or should the other non-grommet end be attached somewhere on the battery itself?
That hose plugs into the side of the battery, under the positive terminal, it's a vent. If there is no place to plug it in, you likely have an acid battery, which is incorrect for the Prius. And not safe for you! The brown connector goes to the left of where the fan connects. In the picture, bottom left corner, you can see the white connector, that's where it goes. I don't believer the car will run without it. The name of it and what it does seems to be hiding in my mind and I can't recall it..... Someone will likely chime in though. The red and black wires are aftermarket. Previous owner might have had an amp, or other powered item. You can probably just remove it.
Previous owner likely put in a non-standard (12 volt) battery, without the vent function. With the battery being in the cabin compartment, it's much preferable to have an AGM (Absorbent Glass Mat) type of battery, complying with the spec's for dimensions, ratings and vent port. Dealership parts department will have them or can order, though if it's like North America you best be sitting down when you get a price quote from them. There's likely third-party batteries availably as well, meet specs and a little cheaper.
Good to know, will check that out! Yeah aware the brown connects onto a clip but it doesn't stretch that far for whatever reason...just floating about, was just interested in its purpose. Guess I'll leave them there for now as put them inside the door side skirt area or try follow them to see where they lead.
There’s a few things definitely not as they should be. “Brown thingy” is meant to be clipped to metal tang on hybrid battery base, and various electrical connectors should be plugged in. Ditto for 12 volt battery vent tube. I took a few pics of ours, attached:
Those clips are just disconnected as was putting everything back together after cleaning the battery fan. That brown one has a clip in the same location of yours however, cable stretch doesn't allow it to go that far. Nor do I have wires going into a grommet like in yours. In regards to the 12V battery thank God, it does have a vent hole, however the hole is too small/hose clip is too big to fit... Now the question is, do I carefully try to enlarge the hole or get some different clip for the hose?
It's supposed to be a tight fit. Look carefully, is that plastic part on part, or two parts? You could wipe some silicone on the and press it in.
