2008 PRIUS NO POWER NEW 12 VOLT BATTERY

Then there are codes or something stored somewhere in the system to the OBD2 port somebody needs to try and get the codes or the battery that's new may not be as new as you think You may want to check that The lights come on how long do they stay on before they start to go dim at least 5 minutes or something close to that not two

 

By "New Dash Unit" do you mean you installed a new car stereo and that's when these problems began? Or something different than that?

 

Yeah, that's called "combination meter." Your symptoms are similar to what happens when the capacitor in that part goes bad, but slightly different. If the combination meter goes bad with that underpowered capacitor it will seem as there's no power or dash lights but headlights will work and power door lock will work. The only difference is despite the dash being out, the car will still drive and powering the car off will be problematic. Can you confirm that car still drives and it's hard to power off? If you can than that's your problem.

 

Check fuses. DOME, EFI, and AM2 for starters.

Any history of jumpstarts prior to the new 12 V battery?

 

In that case I'd read up on parts that need to be replaced when someone tried to jumpstart the car at the jump points with reverse polarity.

 

Define New? A new CM from Toyota or a reworked CM that was new to you? If you got a reworked one, from where?

... that you know of.

Does that include a visual inspection of the 100 A fusible link assembly in the engine room fuse box, all fuses in the under-dash fuse block, and the 5 A fuse in the battery block assembly on the 12 V positive terminal?

Did you check the fuses for continuity with an ohmmeter? Sometimes they look intact but are blown.

Do you have 12 V at the jumpstart terminal in the engine-room fuse box? Do you have 12 V at each of the fuses? Did you test all the relays?

If all of that is good, you need to start tracing the 12 V supply from the battery until you find the break in supply.