No power mystery

This is, unfortunately, a multi-layered backstory that complicates the basic problem of no power. I had stopped driving my 2006 Prius after getting a battery overheating code. It sat for 4 months but I would start it occasionally. Then, this weekend I took the hv battery out to check the cells. I did not try to start it before I took it out, however. I found one obviously bad cell which I replaced and put the battery back in. I may not have seated the orange safety switch the first time I tried starting it, however, but did set it properly after that. I’d charged the 12v battery ahead of time, but there was no real sign of power, except what seemed to me to be a weak power button light and some slight power up sounds when putting on the brake and pushing the button. No dash lights, no screen power. There was 12v power at the jump location. This story, so far, is probably fairly common, and the next part is where some will tune out, so before you do, please let me know what you think the problem is before you read the rest. The other part that may or may not be the problem is that during the time it sat, apparently rodents had gotten in and done some damage. I have taken the dash completely out to look for damaged wires, and so far have only found a couple that could account for the dash lights being out, but they were out the last time I had started and driven it, maybe 3 weeks ago, and it seemed to run fine otherwise, (prior to throwing the code again). I plan to use an endoscope to inspect the rest of the wires that I can’t get to still, but I am not seeing much wire damage, but they were both in the dash and under the hood, and probably in the trunk as well. So, what I am asking for is a checklist of what I should check to get things at least back to a baseline of power to start. I should be able to take it from there. There is 216v at the battery side connection, after the orange safety switch is installed. I am not seeing any voltage on those two main connection points right beside the ones closer to the cells that I got the 216v reading at. Should these points also show full voltage, or only once you are in a ready condition? Any help would be greatly appreciated. Thanks.

 

I will definitely check on the combination meter repair procedure, thanks for that. And also thanks for the info on what really happens getting to the ready state. That makes complete sense.

I have tried two different batteries and both were at least 12.4. One is pretty much brand new. I did check for continuity with my cheap multimeter, and it showed as good, but will probably add a jumper to ground next time, just to be sure, so thanks for that, as well.

I imagine there are a number of conditions that the computer must see as correct, before it allows the ready state. Are these conditions listed somewhere on this board, would anyone happen to know? I might try confirming as many of these as I can.
Thanks again.