Thermos not working

With the car cold and the tray out open the radiator cap and confirm that it is full. Low coolant can cause those codes. If the overflow was normal and the radiator low have the radiator cap tested. If you have not already done so mark the center point of the overflow tank with a sharpie, that makes reading the level there more reliable than just eyeballing "middle".

If the thermos pump never runs, but it will with the relay socket jumpered, it might indicate that the relay itself is bad. Could also just be dirty contacts. Pull it and if the "legs" are not shiny clean spray them with electrical contact cleaner until they are. Inspect the socket itself for corrosion and dirt. It would probably be OK to spray contact cleaner in there, but only if the car was cold and off, as the stuff is flammable.

If the relay tests good and its contacts are good and the coolant level is good I guess you would need to start testing electrical signals starting at the pump and working back towards whatever ECU drives those lines.

 

It might be easier to simply got to a Pick n' Pull and find a similar wrecked Prius and pull the whole thermos and pump assembly out and put that in your car... I've found that if a 3-way valve has been broken for lots of years before repair, the system never seems to work very well after that, compared to a system that was quickly repaired when the 3-way valve failed.

 

But if the pump is not getting power and it runs when we jump it. Then we've got a driving problem of that circuit whatever circuit that may be I'll have to pull the book down literally and look where it goes. I wonder if there's a way to jump her this thing out of the system because I never seem to need it my car either sits too long and the water in the thermoses you know 80° if you're lucky or less and when the sun comes up it'll be $100 outside. In Winter same thing it's so cold out unless you're making short runs I can't imagine that thermos being that efficient I know yeti cups and stuff like that are not what they're all cracked up to be so I've seen these thermoses and had the parts apart they look about equal to a yeti cup but obviously bigger