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New 12 volt, no lights, no jump start, need help

Discussion in 'Gen 2 Prius Main Forum' started by Brett Martz, Sep 1, 2022.

  1. ChapmanF

    ChapmanF Senior Member

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    Also, go to the back of the car and look at the small fuse block attached to the 12 volt battery + terminal.

    There are two fuses there, a large 100-ish amp one, and a small 5 amp one.

    The last backwards-jumped Gen 2 I worked on had that 5 amp fuse also blown, which will cause a DC/DC converter trouble code. That had actually caused a dealer tech (who should have known better) to say "bad news, it's not just fuses, you'll need a new $$$$ inverter too."
     
  2. rjparker

    rjparker Tu Humilde Sirviente

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    First if any fuse, wire or connection has the green oxidation, it has to be cleaned or replaced. The oxidation will eventually prevent proper current flow. Using an ohmmeter on x1 scale on each fuse will test them. It is necessary to remove them one by one, test and then immediately replace each fuse. Otherwise you can and probably will mix them up and or place one in a currently empty slot. Some fuses are called fusible links and are often screwed down. More expertise is needed for them although most fusible links can be visibly inspected. Small mini fuses can be open without the obvious "blown" look.

    Voltage testing of some fuses only works if that system is energized. So voltage is not a definitive test without knowledge of a particular circuit.

    There are fuses in the engine compartment, interior and at the 12v battery. There is a fuse in the orange handle of the hybrid battery but I would leave that one alone.

    If you have excessive parasitic draw, a blown fuse is not the problem. Generally it would be smart to let an experienced person track down the source as it could be any of the hundreds of electronic parts or motors. However the most common parasitic load is a light left on, starting with the rear hatch light.
     
    #22 rjparker, Sep 3, 2022
    Last edited: Sep 3, 2022
  3. Brett Martz

    Brett Martz New Member

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    My New fusible link box assembly arrives Wednesday. I will install, reconnect the 12 volt and check the remaining fuses then. I did visual checks on the 12 volt and engine compartment but only visual check so far. I found this video to help with the replacement. Thank you all. I’ll be back on here Wednesday when the part comes in.
     
  4. rjparker

    rjparker Tu Humilde Sirviente

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    The video does show the difficulty of pulling it out to access the bolt on cables. Some people have major difficulty with this part. It does not really show removing the attached fuse panel from the fusible link assembly but that should be obvious. There are also two plug in connectors on the bottom he does not show. Remember the green oxidation has to go or it may not work 100%.
    D90908FD-F3B9-492D-BBA4-1F2540031F47.jpeg
     
  5. pasadena_commut

    pasadena_commut Senior Member

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    If one of the door switches fails closed it will pull 300mA out of the 12V. There should be a door open light on the dash though, and the dome light would be on (unless it has been set to the "always off" position).
     
  6. ChapmanF

    ChapmanF Senior Member

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    There are several plastic clippy places that have to be released around the edges of the fusible link block so it can be lifted up. There is another clippy place just like those on the attached fuse panel (way down at the forward end of the fuse box). Release at that clippy place, and the fuse panel comes right up out of the box along with the fusible link block. Then you have easy access to unbolt it.

    When I recently needed to replace one, I obtained a used one as part of a whole salvage fuse box, so I had a chance to practice removing it.

    That one was very difficult to lift out of the box. The heavy-gauge wires attached to it and folded underneath do not bend easily. I had to improvise some tools to lever it up, bit by bit. (I have some large external snap ring pliers that are great for that kind of work. I use them more often that way than for snap rings.)

    I found it was helpful to take my time. I could haul it upward by a few mm and then go do something else for a bit, while the heavy wires relaxed into their new shape. Then I could haul it upward some more.

    When I got around to removing the blown one from the actual car, it was a piece of cake. Pulled right up. Not sure what explains the difference, but the salvage fuse box had been sitting, I think, in the sun a long time. It might have been not just heavy copper wires but heavy copper in extra-stiff UV-baked insulation.
     
  7. Brett Martz

    Brett Martz New Member

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    The part came in a day early. I got the old one out pretty easily. Hardest part was getting the two white plugs out of the bottom. I also broke two of the small bolts on the right side removing them so I need to go get replacements bolts. I will get fuses as well. Next step will be install, check other fuses, replace any blown, and then try to fire it up.
     

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    #27 Brett Martz, Sep 6, 2022
    Last edited: Sep 6, 2022
    bisco likes this.
  8. rjparker

    rjparker Tu Humilde Sirviente

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    That fuse box looks like it was flooded, not just wet.
     
  9. Brett Martz

    Brett Martz New Member

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    I bought the car four years ago and have put almost 70,000 miles on it since. I had the hybrid replaced once and 12V twice. I changed the throttle body and cleaned sensors but no other major work. I know that I haven’t had in a flood. I certainly could have sprayed water in there when cleaning and not realized. How long does this level of corrosion take?
     
  10. rjparker

    rjparker Tu Humilde Sirviente

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    Flood damage can take years but usually not four years. Flood corrosion and the dirt coating everywhere would likely be in the interior as well. At this point you need to ensure the fuse box is as clean as possible, perhaps with the help of some dexoit spray.

     
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    I have never seen a fuse box in that poor of condition. Not even in a salvage yard. It needs to have a cover installed to protect it, but the odds of it being too late to prevent future problems is pretty high. I can't even imagine what the fuse holder terminals look like. Spray it, get a cover for it, and hope for the best.
     
  12. Brett Martz

    Brett Martz New Member

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    I installed the new fusible link box. I was able to get accessory on but no further. I have headlights and door locks but no start. I am going to check and change all small fuses tomorrow. Let me know if you have any other suggestions. I was happy to see headlights and computer display today. I know I’m a beginner. I’m just poor and trying to get me daily driver going again. Putting too many miles on wife’s car.
     

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  13. ChapmanF

    ChapmanF Senior Member

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    Don't forget to replace the small black cover that slides into the side of the fuse box to cover the fat 12 V cable where it attaches to the fusible link stud.
     
  14. rjparker

    rjparker Tu Humilde Sirviente

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    Try powering down and attempting a restart to Ready several times. It usually does not work the first time as the computers initially power up. Most likely you have more fuses blown. Be sure to check and return each fuse one at a time. Plenty of people mix them up.

    When all that fails, clean up everything with the suggested spray.
     
    #34 rjparker, Sep 7, 2022
    Last edited: Sep 7, 2022
  15. Brett Martz

    Brett Martz New Member

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    Thank you fuses and spray tomorrow.
     
  16. Brett Martz

    Brett Martz New Member

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    Should I leave the 12V Hooked up overnight or disconnect ground?
     
  17. Brett Martz

    Brett Martz New Member

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    Can you provide pic of exactly what you’re talking about?
     
  18. rjparker

    rjparker Tu Humilde Sirviente

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    I would but it depends on your ability to verify 12v battery voltage and your ability to jump it safely if necessary. A battery tender would be ideal.
     
  19. Brett Martz

    Brett Martz New Member

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    I’ve got voltmeter, a 750 amp jump starter and my wife’s car if s jump is needed. It’s been measuring 12V and 11.8 with high beams on.
     
  20. ChapmanF

    ChapmanF Senior Member

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    I made it transparent green here. It's a little black plastic cover that you slide down into place from the top; its 'wings' go into the slots you see.

    box.jpg

    You can peel the blue off the fusible link window when you're ready. :)