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100Amp DC/DC Fuse Fusible Link Replacement - 15 Minute Job

Discussion in 'Gen 2 Prius Technical Discussion' started by PaulDH, Jan 12, 2021.

  1. PaulDH

    PaulDH Junior Member

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    Thanks much for providing me with a fusible link. Greatly appreciated!
     
  2. PaulDH

    PaulDH Junior Member

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    I have an update. TMR-JWAP was kind enough to send me a good used 100A DC/DC fuse. Many thanks TMR-JWAP!!! I just had cataract surgery two days ago, so although I was anxious to get on with it, I forced myself to wait until today to install the new fuse and test out the 09 Prius. It took all of about 10 minutes to install the replacement fuse and reconnect the HV and auxilliary batteries. So again, swapping out this fuse in my 09 was a very simple and straightforward process. I probably have 35-45 minutes into it on my first effort (and hopefully last effort).

    I installed the fuse and the vehicle seemed to do everything correctly. The Ready light came on, and then the engine has started up and cycled three times so far. With the Ready light 'on' in the dash, I've tested the DC voltage at the under the hood jumper points and get 14.23 Volts. I then tested the voltage directly off the auxilliary battery posts in the rear of the vehicle and I get 13.74 Volts.

    The voltage on the auxilliary AGM battery prior to starting the vehicle read 11.99 volts.

    My handicapp is I only owned this Prius for one week prior to reverse polarity jumping the vehicle and blowing the 100A DC/DC fuse.
    For those in the know, does it sounds like lady luck was with me? Does all seem good? Anything else I should be testing or troubleshooting.

    I did buy a VXDIAG VXC NANO for Toyota vehicle communication interface, but I don't have a laptop here to fire that up yet. I think I can read codes off the radio display, but I'll have to find a good thread on the Forum or on YouTube to do that again. I did it once prior to blowing the 100A DC/DC fuse.

    Thanks much for any and all assistance.
    Paul

    Just tested the voltages again with the vehicle still in Ready mode, and now get 14.07 under the hood on the jump start contacts, and 13.79 on the auxilliary battery.
     
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Glad to hear everything is working out! I'd say you're sitting in pretty good shape. Drive the wheels off of it!!
     
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  4. offib

    offib Member

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    - butting in here -
    if I could add, I had the same 100 amp fuse blown. and two small other ones. But even though a new 100A resurrected the car with ready mode, coolant pump working fine etc, the Screen had two or three red square engine warning lights all over, and after 30 seconds just one red 12v battery square.

    I had the car's power converter replaced with one from a parts car, and then it keeps on running.
     
  5. dolj

    dolj Senior Member

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    While this "worst-case scenario" sometimes is the case, more often than not the 100 A fuse does its job and saves the day.

    But it is worth noting that the inverter can get damaged and need replacing.
     
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  6. tgm707

    tgm707 New Member

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    hi can someone please tell me what the part number is for this, second generation prius, fusible link assembly, the local toyota dealer has literally given me the wrong part twice in a row
     
  7. TMR-JWAP

    TMR-JWAP Senior Member

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    82620-47050 is the number on the side of one I have in my hand. I have 9 on the shelf and they all have the same number. For more info, click on the link below.

    82620-47050 - Toyota Parts Deal

    Any chance a Canadian model is different?
     
  8. ChapmanF

    ChapmanF Senior Member

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    Everybody who discovers that screen gets high hopes about it, but the only codes you can see there are for the car's infotainment systems. Regular diagnostic trouble codes for the powertrain, chassis, and body have to be read over the diagnostic port. (Some of them can also be blinked out on dash lights, if a jumper wire is put in the right place.)
     
  9. HammerGrips

    HammerGrips Junior Member

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    I'm trying to track down some parasitic draw on my 2008 Prius. It had not been jumped for quite a few years prior to this issue and everything else seems to work fine. The problem is the 12v battery goes dead in a very short time when parked. I charged the battery a couple times then swapped with another battery. then just left the battery with jumper cables to the back connections so I could move it occasionally. (it's an extra vehicle now that we're (covid)retired)

    Connecting a meter in series with the battery, I'm seeing about 13A draw with everything off. (yea, monster draw. No wonder batteries were dead within hours) I've pulled every fuse and relay checked that the draw remains unchanged. I'm thinking the fusible link circuits are all that remain.

    I'm open to suggestions on what to try and especially curious about the mention a few posts back abouta power steering unit causing a parasitic draw. Tests, remedies?
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

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    Do you hear anything running while this draw is occurring?
    I had someone connect jumpers backwards and smoke the main fusible link and a couple fuses in the underhood fuse box. It caused the ABS pump to run non stop, which put a huge load on the battery. The abs pump is directly behind the inverter against the firewall. If it's running you should be able to hear it.
     
  11. ChapmanF

    ChapmanF Senior Member

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    At 13 amps I bet you could just about wave a Cracker Jack compass over the wiring harness and follow it to where the drain is.
     
  12. TMR-JWAP

    TMR-JWAP Senior Member

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    yes. There are very very few things on a Gen 2 that would or could draw that much current and not release all their stored smoke..
     
  13. rjparker

    rjparker Tu Humilde Sirviente

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    The last time I Iooked, the Electric Power Steering was about the only load served by a fusible link without another fuse or relay in series. That car's parasitic load was 90 ma, a far cry from 13 amps.

    Hopefully your case is not a wiring short. With 13 amps it may be possible to trace the current draw by measuring millivolts across the individual fusible links in the module. Prius Gen2 Eng Fuse Box & Fusible Link Mechanical.jpg Prius Gen2 Fusible Link Passenger & Drivers Side Views.JPG
     
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  14. DMAndy

    DMAndy Junior Member

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    I am reading this with great envy. I am about 2 hours into replacing my fusible link and am stuck. It only took about 30 minutes to take out the original blown one and wasted 90 minutes trying to put the new one back. I just cannot pull the 2 wires with the 8mm connectors up enough to connect them. How did you do it, if you don't mind me asking? Any help would be appreciated.
     
  15. ChapmanF

    ChapmanF Senior Member

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    Yeah, it seems like in some of these fuse boxes the heavy-gauge wires are stiffer than what you see in people's "look how easy this job is!" pics.

    Steve at Autobeyours sold me a whole old fuse box yesterday to take the thing out of, which I guess is good because it lets me practice, but I'm still trying to pull this one upward hard enough to access those 8mm boltheads. :(

    Edit: ah, just got it, first try this morning.

    I think time is helpful. As I was pulling the sumbtch upward last night, I noticed I could kind of pry it up by a cm or so, and leave it that way a while, and the wires kind of relax into that position, and then I could pull it a little further, and I could do that several times.

    After leaving it that way overnight, I found I could pull it just now clear past the top of the fuse box, and without much difficulty.

    Edit again: oh hey, and with another emphatic yoink, it comes up a good couple inches above the box. The wires really are long enough, but just awful stiff.

    The one that attaches to the inboard side of the link block is a shortish one that just plugs into the bottom of the integration relay (the one with the four fuses, not the one with blanks). Maybe in some cases it could be helpful to unplug that from the integration relay first.

    I have a heavy-ish external snap ring plier, for transmission work, that ends up being pretty useful for persuading the two four-pole plug-in connectors out of the bottom of the link block.

    Edit again again: Great. The one he sold me has the 30 amp RDI segment open, the one that supplies the blue-wired cooling fan on high speed. Everything else is ok.

    Because I bought the whole fuse box with this thing in it, and drove it home, and couldn't easily test all the positions for continuity before wrangling it out of the box ... grr. The thing is only $97.40 MSRP at the dealer anyway, I shouldn't have bothered.

    But at least this way, I got practice with how it comes out of the box.

    It might be handy for somebody to make a list of all the easy places to check continuity of the different fuse link segments before wrangling the thing out of the box. For example, the RDI segment can be checked at the red wire, 3G position 1, under the four-blanks integration relay. Checking there would require popping that relay out, but that's marginally easier than hauling the fuse link out.


    Edit again: and no, the open segment wasn't something you could readily spot, looking through the clear cover. If you popped the cover off and wiggled the top part of that segment with a skinny tool, you could see that the bottom part didn't wiggle with it.

    Maybe the easiest way to check one of these is to pop the top cover off, then carefully touch just the bottom part of each segment with an ohmmeter probe, careful to keep the probe away from the top part.
     
    #35 ChapmanF, Jul 30, 2022
    Last edited: Jul 30, 2022
  16. ChapmanF

    ChapmanF Senior Member

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    Ok, I just did this job on a Gen 2 where the owner had been told by the local Toyota dealer that definitely the fusible link and the converter were toast. So I picked up a fusible link and an inverter and I started with the easy job.

    Though I had needed to pull very slowly and very hard to get my 'practice' fusible link out of a salvage fuse box because the wires were so stiff, the one from the actual car pulled out much more easily. Maybe because dealer guys had already pulled on it once.

    Besides the link, three individual fuses got eaten. In this story, they were ABS-1, DOME, and DC/DC S (the little 5A one in the battery clamp). The DC/DC S one causes a converter code. Maybe that was the whole reason the dealer thought a converter was needed. Moral: don't forget to check that fuse.

    Because of the ABS-1 fuse, there was one C1242 code to be cleared at the end of the day. Other than that, this was easy and much less expensive than the dealer estimate.
     
  17. AlohaBilly

    AlohaBilly New Member

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    Just had this exact situation happen to me as well
    ( 5A #49, 10A ETCS #36, 15A dome #39, and the same spot blew in the 100A DC/DC fusible link)

    I am praying you still have have some left over you'd be willing to sell.
    not sure how to write on your profile since this is my first post / comment.

    all of the advice on here was spot on and made my life a little easier. huge thanks for everyones input!
    - Billy