Need help, reversed polarity installing new aux battery

Yeah, that was what I figured, just a case of using the jargon imperfectly, not of doing bonkers stuff. I don't know why we're so gung-ho around here to pile on to new members and say "I can see you're hopeless!!!". The terminology is learnable; you can probably find online resources that are good.

If you think it's part of your problem, you can go ahead and take yours out of the picture, costs you nothing (well, unbolting one connection and unplugging two others). Then see how much of the rest of the car's 12 volt system you can get working, and get talking to the ECUs. Yes, the HV ECU will say "huh? what, is my inverter unplugged?" but as a first step that proves it's alive and talking.

Nothing wrong with buying an inverter if you want, and then you'll have it if you need it, but you can do plenty of the rest of your troubleshooting by just eliminating yours temporarily from the picture.

 

Ok stop dude you have no idea what you’re doing in this circumstance.

Let it go don’t spend anymore time and money on this.

 

Some of my most valuable learning experiences were when for some reason I had to go into something without, let's say, ideal preparation....

 

When I press the start button once, it turns green, but none of the instruments come on.

Assuming this "one push" is done with foot on brake....

Why in the world are we talking about replacing an inverter when the dash isn't even coming on? What does the inverter have to do with the 12v system prior to going to "Ready"? Answer....not a damn thing.

Quit pissing away your time and effort chasing ghosts. The 12v system supplies all the power to energize the dash/mfd, etc. Perhaps you smoked the power source ecu.

Looking through the driver side window, there should be the small car shaped icon flashing
Open the driver door and the door ajar light should come on.
With foot off brake....one press of the power button...green led comes on, mfd comes on, clock comes on, radio comes on
With foot off brake...second push of power button....led turns to orange...rest of dash comes alive

Then...
With foot off brake...third push of power button...car/system shuts off
With foot on brake...third push of power button will put car in ready mode (just as if the first push was done with foot on brake)

 

If you haven't yet, take a read through this thread. Not exactly the same, but it's similar symptoms.

2005 prius will not start but 12v battery seems to be working | PriusChat

 

Negatory. First off, the inverter and converter are turned off at all times except when the car is in READY. If the car is OFF and you can't get it to READY, it is normal for the inverter and converter not to be doing anything.

Now, Ed's hypothesis, which may have some merit, is that the output section of the converter sustained damage and could now be pulling the 12 volt bus down through its fat white connection to 3E. That would have you not seeing battery 12V anywhere, unless the 100A DC/DC fuse is open, in which case you could see battery 12V at places like ABS-1, DOME, and HAZ, but not at places like RDI, HTR, FR FOG, DOOR, or OBD.

If there does seem to be a large drain pulling down the whole 12V bus, unbolting 3E would tell you right off whether it is the converter output section doing it.

The skinny circuit DC/DC-S ⟶ IN1 ⟶ C5(3) is not power to the converter, it is merely there to allow the converter to sense the voltage at the 12 V battery. There is more to the converter than the two terminals shown on p. 64. You meet it again on p. 105. It gets its power from terminals I12 and I13 (p. 103), fat orange wires from the traction battery. (Turning that 200+ volts DC to 14 volts DC is what makes it a "converter".)

There is no power on those orange wires except when the system main relays (inside the traction battery case) are told to close by the HV ECU. Again, that never happens except when the car is READY.

I don't remember seeing you list which of those do currently show +12 with the battery connected and which of them don't. Have you taken your meter to all of those? It would be useful information to have here.

My sense so far is that there is a problem cropping up before the Power Source ECU is ever persuaded to close the IG and ACC relays, and before the HV ECU is ever persuaded to bring the inverter/converter online. That's why my time would be spent continuing to check the 12 volt system, with the goal of reestablishing communication with as many ECUs as I can, then asking them to comment on the situation.

 

Wait, what? You're saying you do show power at those places?

Those are downstream of the IG1 relay. Those should be off. Can you make them show no power by pushing the power button again?

If you can't, try pulling out the IG1 relay. (The power at those fuses should definitely go away when you do.)





With the relay pulled out and in your hand, what does the ohms setting on your meter show between its pins 3 and 5?



With the relay removed from that socket, what voltage to you see from pin 2 of that socket to body ground (or to pin 1 of the same socket)?

 

I think the fuse box itself is relatively less likely to be the culprit. It's mostly stamped pieces of metal in there, that would have to be some serious frying action.

There are a lot of things downstream of the fusebox that get power from more than one place (think of the earlier example of the clock, with a constant B source for timekeeping and also an ACC input that controls the display). I would sooner guess one of those things was damaged, formed a bridge between its constant B supply and its IG supply, and is backfeeding that IG1 branch through its fuse.

Without putting the relay back, pull out all of those seven downstream fuses. If you still see +12 at those fuse sockets or at pin 3 of the relay socket, something has happened internal to that junction box.

If the voltage has gone away, put those fuses back in one by one and note which one makes the voltage reappear.

Of course double-check that the relay you pulled is the relay you think you pulled.

 

Make lists of the things downstream of each of those three fuses.

Edit: waitaminnit, whaddaya mean OBD? That's not one of the seven fuses downstream of IG1.

One has to be rather detail-oriented doing this stuff, or it gets hard to draw conclusions from the results. I thought you were going to pull ECU-IG, WIP, WSH, GAUGE, RR WIP, M/HTR. and A/C(HTR).

Do you see in the diagram why I thought that?