No power to vehicle?

Tiny
2OVERPAR
  • MEMBER
  • 2017 TOYOTA MIRAI
  • 2WD
  • AUTOMATIC
  • 60,000 MILES
Battery was dead in my 2017 Mirai, so I removed the battery and charged it outside the vehicle. Reinstalled the battery and when I hooked the battery cables, the alarm went off, indicating power. While tightening the connections, ratchet was on the negative terminal and the wrench slipped and hit the positive terminal creating a quick arc. Now I have no power to anything - a 2017 paperweight. I have scoured the web, but there is very little info on the Mirai and the owners manual is of no help. The fuse block diagram is abbreviated, so of very little help. Any thoughts would be greatly appreciated.
Monday, August 11th, 2025 AT 8:58 AM

9 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yep, that is a bummer, you almost certainly blew a high-amp main fuse or fusible link that sits between the 12V battery and the car's electrical bus. Here is a guide to help test the fuses

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Here are the fuses that need to be checked. Check out the images (below). Please upload pictures or videos

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Monday, August 11th, 2025 AT 1:29 PM
Tiny
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Ken,
Thanks for your prompt response. I have checked any fuse that by the abbreviations on the inside of the block cover seemed to pertain. How do I test the 60Amp or 180 amp fuse? I have already replaced a relay but that did nothing. Are the images general or vehicle specific?
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Monday, August 11th, 2025 AT 4:28 PM
Tiny
KEN L
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These images are for your vehicle, I would use a test light to test the maxi fuses, you might be able to see them as well, if you upload an image of the fuses I can tell you more.
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Tuesday, August 12th, 2025 AT 8:28 AM
Tiny
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Ken,
Thank you again for your responses - I was told that these vehicles carry enough voltage to kill a person and at 71 it wouldn't take much. I may just have it towed to a dealer not risk getting my hair curly.
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Tuesday, August 12th, 2025 AT 3:26 PM
Tiny
KEN L
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Yes, they do but you are dealing with the 12 volt system which you will be safe, I would not let you hurt yourself :) Please let me know wat they do to fix it.
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Wednesday, August 13th, 2025 AT 9:35 AM
Tiny
2OVERPAR
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  • 5 POSTS
Ken,
Finally had a chance to check out the fuses with the diagram that you sent and it was the H830 180A fuse that blew. Now I can't figure out how to remove it to replace it. Any thoughts? And thank you for the diagram, it took we a little while to figure it out.
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Sunday, August 17th, 2025 AT 3:46 PM
Tiny
KEN L
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You are welcome, that is all they show. Can you upload an image of the fuse so I can see what to do?
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Monday, August 18th, 2025 AT 10:33 AM
Tiny
2OVERPAR
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Ken,
First off - thank you so much for you and the other mechanics that take the time to help on these forums. I tried to find the part online, but didn't see anything similar, so I called the parts department at Toyota and that part (that shows the blown 180A fuse) comes as a complete unit, and not that pricey - under $40. They are ordering it and I should be able to pick it up tomorrow.
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Monday, August 18th, 2025 AT 12:32 PM
Tiny
KEN L
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Nice work!. That should fix it :)
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Monday, August 18th, 2025 AT 1:05 PM

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