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Need help, reversed polarity installing new aux battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by DMAndy, Aug 28, 2020.

  1. jdenenberg

    jdenenberg EE Professor

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    I would find a good electronics technician rather than a mechanic. If you were domiciled in the Midwest US, I would send you to Steve at https://www.autobeyours.com and he would fix your Prius at a reasonable cost (He would have all the salvage parts needed on his shelf).

    JeffD
     
  2. DMAndy

    DMAndy Junior Member

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    Thanks Jeff. Unfortunately, I am in England.
     
  3. DMAndy

    DMAndy Junior Member

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    OK, bear with me for a moment.

    Getting back to my idea of fixing the clock will fix the car. The clock wiring diagram is on page 306 of the book and looks much like this:

    upload_2020-9-2_16-23-36.png
    According to my limited understanding of the diagram, the clock needs current from three sources. The DC/DC fuse, the ACC fuse (#24 in the cabin) and the dome fuse (#17 in the engine bay). Now, I have current at the DC/DC fuse and the dome fuse. I do not have current at the ACC fuse. Now to figure out what feeds that fuse...
     
    #43 DMAndy, Sep 2, 2020
    Last edited: Sep 2, 2020
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    Reading this thread is killing me. I've been involved in some 'reversal' scenarios previously, including one where a young lady and her friend connected a spare 12v battery to the 12v battery in the trunk (using jumper cables) to act like a booster, but connected it backwards, and left it like that, fairly quickly killing both batteries and the car. The main fusible link (in the underhood) fuse box and 3 fuses in the underhood fuse box were blown. No, I don't remember exactly which fuses they were.

    So, it sounds like you found the main fusible link in the underhood fuse box to be open, and installed a jerry rig to bypass it. Is that correct? If so, doesn't this mean you have to eventually replace it with the correct one? If so, why not start with replacing the fusible link now, to eliminate a bunch of tail chasing that may be due to something being not quite right at the fusible link.

    Without being there to put my hands on it, I just see a lot of crap going on that makes me wonder if it's a lot of tail chasing..

    Maybe, this weekend, I'll just go ahead and hook a battery up backwards to my 341k mile 2006 to simulate what you did. Then I can troubleshoot it and see what I come up with. The only part that worries me is the entire situation was thrown out of whack when you started disassembling ecus and such. That throws an awful lot of potential variables into the mix that I have no way of duplicating.
     
  5. DMAndy

    DMAndy Junior Member

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    That Prius is a treasure, don't you dare ruin it. Also, I am pretty sure doing the exact same thing I did might produce different faults, if there was a way of doing everything exactly like I did.

    After I replaced the ECU, the car is producing the exact symptoms are before I took it out. I could have introduced new faults, but for the sake of my sanity, I am going to assume I haven't.

    I am happy to replace the fusible link once I make a bit of progress, but I hear it isn't particularly easy to do and there don't seem to be used ones on Ebay.
     
  6. DMAndy

    DMAndy Junior Member

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    OK, according the the power sources flow chart, 100A DC/DC -> 25A ACC-B (#12 in cabin) -> ACC Relay (point side) -> 7.5A ACC.

    I have current at 100A DC/DC, but not at 25A ACC-B, and hence neither further down the line.
     
  7. TMR-JWAP

    TMR-JWAP Senior Member

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    Now to figure out what feeds that fuse...

    Perhaps, the main fusible link assembly, (the large rectangular, white plastic box on the passengerside of the fuse box, with the clear lid) has several fusible links inside, of which each one supplies power to portions of the fusebox?

    If you look where the main power cable comes into the fuse box, it bolts to the top of the main fusible link. Power then passes down the busbar in the fusible link and is distributed to several smaller fusible links. Each of those smaller ones supply different circuits of the fuse box.
     
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  8. TMR-JWAP

    TMR-JWAP Senior Member

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    The fusible link is easy to replace and takes about 10 minutes. Probably 30 for a 'never did it before' DIY
    Just off the top of my head:
    1. Unbolt the main power cable at the upper left corner, unlatch and remove the plastic clamp that holds it to the fuse box, lift cable and move it out of the way.
    2. The FL has a handful of clips that hold it in place. i use a small flathead screwdriver (tweeker) to pull the clip back, and insert the tip of a small ziptie into the gap to prevent the clip from re-engaging when I release it. Do this to each clip.
    3. The FL can then be lifted upward slightly. The small fuse holder assembly will be attached to the bottom edge of the FL. Disconnect it.
    4. Pull the FL up further to access the 10mm and 8mm bolts that fasten distribution cables to it. Document the cables/photograph, whatever. remove the fasteners and lift the FL higher to disengage (3?) plugs from the bottom.
    5. Reverse it to install the new one.
     
  9. DMAndy

    DMAndy Junior Member

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    OK, so probably an hour for me.

    Thanks for this, I will need it once I have a bit of hope of getting it running again.
     
  10. DMAndy

    DMAndy Junior Member

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    So far, I have traced it back to Center Connector No. 1, if I did everything right.
     
  11. ChapmanF

    ChapmanF Senior Member

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    The terminal names shown on the diagram for the clock give some hints as to what those three supply connections are for. The clock does not display when the car is off, so it relies on the supply coming in at connector C9, terminal 4, labeled ACC, which has no voltage when the car is off, to know when the display should be on.

    By the same token, it has to keep time even while the display is off, so the supply coming in at C9 terminal 1 (B for Battery), which is never switched off, powers the timekeeping.

    But they don't want the clock to blind you when you are driving at night, so C9 terminal 3 (ILL+, for ILLumination) will see when you have turned the tail lamps on. It uses that input to reduce its display brightness to something more suitable for nighttime.

    The ACC fuse of course is downstream of the ACC relay, and never powered when the car is off. You have to go at least to ACC mode (first push of the power button without using the brake) to have ACC power. If you are not able to to use the power button to go to ACC mode, then you don't need to look any further for why you do not have ACC power.

    There are probably any number of well-written electricity tutorials on the web where you could make sure that when you say 'voltage' or 'current' you are using those two different terms in the right ways.
     
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  12. DMAndy

    DMAndy Junior Member

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    Thanks for the details ChapmanF.

    When I press the start button once, it turns green, but none of the instruments come on. I'll double check if I have power at the ACC fuse tomorrow.

    It seems I meant power when I said current above.
     
  13. DMAndy

    DMAndy Junior Member

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    And I was wrong. It is actually the engine room main wire.
     
  14. ChapmanF

    ChapmanF Senior Member

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    Toyota's naming (or the English translations, anyway) can seem kind of goofy. What they call a "wire" in one of these official part names turns out to be an entire bundled up wire harness. The "engine room main wire" is one of the biggest of those, with about a bazillion (plus or minus eleventy-seven) wires in it, coming out to a whole bunch of different connectors.

    When you're a little more familiar with the layout of the wiring diagrams (there is an explanatory section up front), you'll be able to refer in your posts to specific connectors and terminals (as I was doing with connector C9, for example, up in post #51), and the benefit there is that those of us following along at home then know unambiguously what you're referring to.
     
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  15. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    What do you mean "none of the instruments"?

    Do you hear relay clicking from the back? Do you hear the brake booster trying to prime with the brake pedal before you press the button? Does the MFD come on? Flash? Instrument cluster, do ANY of the lights light up (idiot lights, speedometer, etc)? With the car off do you see the flashing immobilizer icon on the instrument cluster?

    If none of that, you still have a basic problem.
     
  16. DMAndy

    DMAndy Junior Member

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    Sorry for not being very specific. No MFD, the two lights on the dashboard that light up are the door open one and the yellow check engine light flashes if I press the button again. And then you hear everything shut down. I'll have to come back to you on the other questions.

    I have taken a quick look at some of the diagrams again and the inverter is finally looking like a candidate for replacement. I'll have more tomorrow, because it's 10pm here.
     
  17. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Extrapolate on what exactly you hear. Catalog it next time you're out there. Also keep in mind a bunch of failed starts, you may drain the HV battery, if it is actually getting connected.

    Turn off all your HVAC (if you can, but without the MFD, probably not) just so you're not competing with fan noise and the AC/vents etc.

    I'd really like to know if you hear the 3-click startup from the battery. If the battery is being connected into the system for the inverter to start going, but it is not, that's different (and bring potential HV battery discharge!) than if the inverter is getting no power and no HV.
     
  18. edthefox5

    edthefox5 Senior Member

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    What is extremely unique and horrifying is you bolted it together reverse polarity and then checked your lights and
    They worked which means it’s not a fast big spark event oh shit I put the jumpers on backwards yours was bolted on backwards then smoked the 100 amp hard fuse yes it pulled 100 amps plus which makes me believe you probably have a burnt harness to boot.

    And the fact your talking about current when checking fuses means your really not up to this task.
    Why are you doing current checks? It’s a meaningless metric just make sure you have 12 volts on every fuse.
    There will not be any fuses with current going through them the Car is dead Jim.

    The inverter going dead will make the hybrid vehicle ecu go nuts and in turn pull the can buss down.
    Strictly my hypothesis.

    I would buy a used inverter off eBay and throw it in. There cheap.

    But the more you post the more we can see you are not at the level that will be able to repair this.
    No shame. Lesson learned. Don’t put a lot of money into it.

    Btw. 2k why are you weighing into dopey posts you got alot of work to do orders to get out lol.......
    Good lord you got 9000 posts on my your out of business post your welcome lol....
    Thanks buddy,.....
     
  19. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Definitely the scary part. Reverse voltage spikes cause tons of damage. Reverse polarity accidents that the TVS's can handle are oh-shit moments, and sometimes they survive. Reverse polarity that sits there and operates like that for human time is an execution.

    I am 99.9% certain it isn't the case here, but I do current test fuses myself. You can get a popped fuse that doesn't explode everything and then there's just a bit of metal shards connecting the two ends. Apply a voltage and measure the other side you'll get something close to what you put in. The resistance will be high and the current carrying ability is gone. But it can fool you. In a car with automotive fuses, generally doesn't happen. But I am used to it now. Or more often than not, just toss it and replace the fuse if I suspect it is bad. It's a 2 cent part, my time is worth more...

    Agree again. I think it is a curious project if you want to breathe life back into it. But curious projects are rarely financially sound.

    We're sold out. So I can sit back and relax again lol.

    Not sure if I should thank you for 9000 views about being out of business or not lol.... Either way, I've got no wares to sell at the moment and won't for 2 months now since the next 2 batches are already completely sold out with pre-orders.
     
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  20. DMAndy

    DMAndy Junior Member

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    No, I did not check the lights. The lights came on by themselves, which made me aware that something is wrong.

    When I said I checked the current, I meant I checked if I had a reading of 12.4 volts.

    Yes, I am obviously not up to the task. But hey, here we are. Also, yes, that's why I am managing what I spend on. So far, I have spent the equivalent of about $25, so I am good.