2005 #P5 No speedometer dash lights out,can not turn off,can not open back door.

How old is this battery? What are you test numbers? Are you testing the battery after overnight rest for full charge? How are you charging it?

 

I'd first test the 12v battery. If it's for sure good, do a search on bad combination meters. Your symptoms sound to me like either could be the cause, but of course the battery is the low hanging fruit.

Matt at @Texas Hybrid Batteries might be able to help you know for sure.

 

The three symptoms that you've described are all caused by a failing combination meter.

I doubt that there's anything wrong with your auxiliary battery especially if it's been replaced in the last couple of years.

Matt

 

I agree with Matt, too.

If you are handy with electronics you can fix the combination meter (CM) yourself. Also, as you have a 2005, the CM in your car will stop counting the miles at 299,999. As you need to fix the CM anyway, you could take this opportunity to replace both the CM and the light cluster (with small mod) which can both be supplied by Matt @Texas Hybrid Batteries. In addition, the replacement can be programmed to the exact milage of your old one. Finally Matt will take your old broken CM an give you a core refund for it which makes this fix quite affordable.

If you are interested to know more details, read the thread linked in my signature (Combination Meters that stop at 299,999 miles...)

 

Do NOT test the battery while car is running! Test it after not using 12 hours/overnight. To clarify: Are we correct that you have recently replaced your 12 year old battery (for the very first time) only 3 months ago? If so, I'm wondering if you have ever fully charged your new battery.

 

If 12v is ruled out, sounds like Combination meter issues.
Plenty of info here on PC on how to replace.
Good videos on Youtube.

Else find your local hybrid repair guy.