07 wont start with out jumping from under the hood(has new 12v battery)

I have a 2007 prius, i replace the original battery with a Optima prius battery about 3 months ago, Never have had any problems with the car but old battery was getting weak. After replacing the battery everything was still normal. Two days ago i came home shut the car off and went in. Next day i had no power(nothing dome light, locks, etc like 12v battery was disconnected), thought maybe something got left on so i jumped it under the hood and it started and ran fine. Let it run for about 30mins turned it off then went to turn it back on, again nothing, I checked the Optima in the trunk and its fully charged and the main 120 fuse is good and all other fuses i can find also are good, But the car has no power to anything or less i jump it from under the hood, jumping it at the optima does nothing. I followed the 12v battery wire till it went through the floor pan under the rear seat still had 14.6v. Cant tell where the wire goes but the fuse box under the hood has no power. Have also tried another good battery with same results. Is there a fuse hidden some where or could this be a problem with the inverter? I have jumped the car a few times and it will start up and run fine and gas motor will even cycle on/off like normal. Does anyone have and ideas what to try or where to look next?
Thanks

 

Thanks its what i have been trying to do. I know the 12v + wire runs along the under side of the car and comes up the firewall along with the orange inverter wires. I can see the inverter wires on the firewall but cant seem to locate the 12v+ after about 8" from the fuse box. Hoping there was a junction or rely i keep missing.

 

A picture from the plug under the read seat to its next connection would be great. I have already tried re-grounding the battery even through the stock ground and ends are still in good shape. I have tried looking online for wiring diagrams put have had no luck in finding the 12v battery schematics.

 

Thanks it conformed no fuses i missed. Finally found the problem. Wire was corroded half way up the firewall inside the plastic sleeve. Now i have to either replace the wire or add a new section in and remove all of the corroded wire. Just glad it happened now and not two weeks ago when we where on vacation Honestly don't know how the prius started for the last few months as bad is it was.
Thanks everyone

 

Yep, trying to see how hard its going to be to replace the whole wire or if i should just solder a section in. May have to wait till the morning to see if toyota even has one in stock

 

Most likely what i will do, cant go anywhere till tomorrow anyway. Plus have to double check how hard it is to remove the the plug ends and reuse them

 

thanks i have searched the forum off and on for a few years just never made an account, Have had the car for about 3 years and have put around 120,000 miles on it. This is the first time its not been drivable for more then a day since we have owned it. Still very happy with the car. Has made 7 or 8 trips to Florida mostly Destin or Clearwater but as far as Miami from Blanchester, Oh. Plus many trips to tenn and other out of town trips and been my wifes daily to college and work also.

 

Would love to visit England one day but we have to save our out of states travels till we are older. Wish mine only had 90,000 i am well over double that. Think she is pushing 240,000. I was surprised about the wire. Only reason i found the break i finally started feeding the wire to see if i missed any fuses and it had a small bubble. I would have tested the wire but thought i was missing a fuse or rely, only because its hard to believe out of no where the problem came out.

 

Thanks, now only if i had an extra one laying around.....