I drove my '05 car no problem Saturday night. I went to start it up Sunday and there was no response at all. There's no dome lights, no dash lights, no power button light, nothing... I don't think any light was left on. The 12v battery was replaced about 1 1/2 years ago. I tried jumping it at the front terminal under the hood but still no response. I checked the 120A fuse connected to the 12v battery and it looks fine. I know there's also a 5A small fuse by the 12v battery, but by this time it was getting too dark to check it. Any suggestions?
Use multimeter. Check the voltage at the terminals under the hood (engine/ground to positive terminal) and at the battery terminals , and tell us. That would be a start of the troubleshooting Alex
looking at a fuse isn't a good test. you got to use a meter. also that 12v battery might have an internal short or something.
I thought I bought a multimeter a couple years ago, but can't find it since moving 6 weeks ago. I'm going to pick a new one up tomorrow, and I will post the results. Thanks!
Try turning on the headlights. If they do not work then you have a problem with the 12V battery or the 120A MAIN fuse. It would be very unusual for that fuse to blow. With the jumper cables applied at the jumpstart terminal and unpainted body metal, see if the headlights will turn on. If they do not then there may be a problem with the way you've connected the cables.
Do you know how to connect the jumper cables to the terminal in the front of the car? The positive goes on the terminal, the negative goes on an unpainted part of the engine. I suspect you have a dead 12v battery
Wow, it's 0.88v at the battery, and 0.5v at the front terminal. I only tried jumping for 2 minutes before. Not sure if it can be saved from complete discharge...
Just got it going again! Jumping it from the front under the hood terminal wasn't doing anything. Even while jumping, checking the voltage at the battery it was still 0.88v. I watched 3 videos, all of them showing the same way. The second I hooked up the live car battery to the actual battery in the back the dome door light went on, and it was up and running in a few minutes. I don't know why the terminal under the hood was not working for me.
When the Prius is READY, measure the voltage across the 12V battery as well as at the dedicated jumpstart terminal, to body ground. You can try to charge the battery overnight, but you will probably find that it is time to buy a new 12V battery or get a replacement under warranty.