Fully charged 12v battery, yet no instrument lights.

Discussion in 'Gen 2 Prius Main Forum' started by Tynyyn, Jan 16, 2021.

  1. Tynyyn

    Tynyyn Junior Member

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    Ever feel like life isn't going your way? Well, this week has been one for me. To make it worse I'm just too darn lazy from being beaten up to do any further research on my own, thus I'm tossing this out to the gurus of smart on Prius chat to help a brother out.

    2006 Prius with 260K on the clock. Don't drive it much any more. Just a couple of blocks down to a job site where I'm building a house. Probably a 1/10 of a mile. Well, after about a week of these travels I am left stranded at the jobsite because the 12v battery dies. So I figure I just need a jump. Cannot open the tailgate because the lock is powered by the 12v battery. Gotta unload all of my tools through the rear doors, pry up the hatch floor and then try to lift up on the spare tire tray so I can get to the emergency hatch release. About now I'm ready to cuss like an Argentine sailor yet I hold my tongue. Get the hatch open and "voile" there is the battery all nice and dead. Get the wife to come down and jump the Prius, take it home and plug it into my battery charger. 100% after a few hours, so I'm happy and life continues.

    Now....wash, rinse, and repeat the last paragraph about four times and I'm at the end of my rope with this drain of the 12v battery. So I picked up a Walmart battery booster. About the size of a deck of cards and it is suppose to help your battery charge up. I had previously run 12ga wires from the battery terminals down through the battery support shelf and out the bottom of the car so I could easily hook the Walmart booster to the battery without having to fight with a non operational rear hatch release.

    After I hooked up the booster the lights on the dash began to flash on and off. I could not pull the key out of the ignition and I guess finally the battery drained from the flashing dash lights and the key came out. Now I've had the battery charger on the 12v battery for a day and it says the battery is 100% full. Go and try to start the Prius and it will not start, no dash lights or head lights.

    Thus I am here to ask for assistance, wondering if there is a fusible link near the battery leads or is there one in the fuse box in the engine bay. (Probably the engine bay). Where else should I look for a possible answer to why my car will not start. I was frustrated that the fusible link is hard to extract and a little pricey. But if that is what must be changed, so be it.

    Got any answers to my plight? Thanks for reading this missive and I hope you guys have a nice day.
     
  2. bisco

    bisco cookie crumbler

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    the battery is probably bad, 100% of zero is still 100%. how old is it? driving a couple blocks a day is just beating it with a sledgehammer.
    i would start with a load test. call around to auto parts stores, they are usually free.

    i don't trust battery charger measurements, put a volt meter on the jump point under the hood and turn the headlights on.
     
  3. mr_guy_mann

    mr_guy_mann Member

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    You should use a digital multimeter and check for voltage at the underhood fuse box on the driver's side. This fuse box also has a little metal lug under a red plastic cover - this is where you are supposed to hook up your positive lead for boosting or charging. I grab a strut mounting stud on the shock tower behind it for a negative connection.

    Anyway, grab a voltage reading there and report back. Yes there is the main fusible link assembly in that fuse box and if it's bad then it requires a bit of disassembly to change it.

    Posted via the PriusChat mobile app.
     
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  4. edthefox5

    edthefox5 Senior Member

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    You did that backwards. Use the underhood front jump point first that’s why it’s there. If the car is locked use the key in the fob. Make sure the door key hole is well lubricated many a Prius owner found after a dead battery that door lock was never used and now is rusted stuck.

    but now that the battery is dead and needed a jump it’s probably toast and needs to be replaced. If you had a voltmeter we could prove it.

    many reports of phantom 12 volt drain most just an old battery or a good battery that was killed perfectly by leaving a light on and now won’t hold a charge.
    Some are a bad 12 volt battery brake back up supply the box right next to the 12 volt battery.

    I do know for certain a G2 Prius is the last car in the planet you want to jump start the story’s we regularly see here of jumps gone wrong are ridiculous
     
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  5. SFO

    SFO Senior Member

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    Assuming a healthy 12v battery, try turning off the SKS feature (if you have it), which may prolong the life or 12v state of charge.

    Going forward, you may have to drive/ready the vehicle for more than 20 mins per week to maintain a healthy 12v battery.

    How many years has it been since this 12v battery was last replaced?
     
  6. Tynyyn

    Tynyyn Junior Member

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    I've had the Prius for about two years. I can only surmise the 12v battery is original.. I've never changed it out. About two months ago I took it to Oreillys and they said it was good. My battery tester/charger says its good. So I guess the next time I have a good weather day I'll go out and look at the fusible link under the hood and do a load test at the red lug.

    I really appreciate all the replies. It's nice to get advise for such a trivial matter, yet if it were any other car than a prius I probably wouldn't be needing assistance. The hybrid battery scares the life out of me. I'm so afraid to touch any electrical component thinking it is directly connected to the hybrid and I'd become a piece of toast quite fast.

    Thanks again for the help.
     
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  7. edthefox5

    edthefox5 Senior Member

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    Ok..but .why are you looking at the fusible link?

    Do you own a fluke quality voltmeter? If not buy one asap you are going to need one.if you had one we could test that 12 battery real fast but really your best play is just replace it. You do not want to mess around with 12 volt issues on a g2 going to be long winter,

    And there’s very few places on a g2 to meet high voltage as an owner or dong casual maintenance. All high voltage leads are Large and orange
    Just like the douche who’s leaving the White House.

    But I’m afraid the truth is sooner or later the high voltage battery and your wallet are going to have a very close relationship.
     
  8. jerrymildred

    jerrymildred Senior Member

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    This is to be expected. You don't drive far enough to recharge what the battery loses while sitting.

    That's doing it the hard way. As Mr Guy Man said, there is a place for that under the hood in the fuse box. Page 362 in the 2007 owner's manual. Yours might be similar.

    Naturally. ;)

    Booster? Is this a jump pack or a charger?

    You might also have a loose or corroded connection.

    THIS!! (y)(y)

    I wouldn't be surprised, after pulling the battery that low and keeping it that low if you find that it's well and truly shot by now.

    As for any high voltage, if the car is off, the only way to get in touch with high voltage is to remove some panels from the cargo area and take the case off the traction battery. If it's on, don't mess with the big orange cables.
     
  9. Tynyyn

    Tynyyn Junior Member

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    I finally had some time to check out the voltage. Had my handy dandy volt meter in hand and opened the hood. First I pulled the clear plastic cap off the fusible link. Eyeballing the link, each node was intact, the small wires ziz-zaggin were not burned or broken. I took a real hard look at them with a flash light and all looked to be in great shape. No burn marks near or around the link, so I can say that it is not the problem.

    Next, onto the plastic red lug cover. I set my volt meter to "20" and touched the red lead to the positive red plastic covered lug and the black lead to a nut on the strut tower. The reading I got was "0.62" Guess that means less than one volt. (As you might can tell I do not know how to use a volt meter. Should I use the "20" or "200" setting?) So now I take my toy and go to the rear of the car and see how many volts are in the battery, itself. Red lead on larger positive battery lug and the black lead on the smaller negative lug. With the volt meter set to "20" I get a reading of 2.15. So I can only surmise my battery has went tits up.

    Few more questions, though. Is there an in-line fusible link close to the battery? Could there be some sort of fuse on the positive cable? Could the positive battery line have a burnt portion which might be touching the chassis?

    Thanks again, y'all. The feedback you've given me is most helpful. I hope the description of my troubles has been clear enough so you can ascertain what is wrong with the car. If I should just replace the battery, please just say so. If there might be any other potential areas I should be looking at for the cure I'd appreciate that info also

    Have a great evening.
     
  10. bisco

    bisco cookie crumbler

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    start with the walmart booster. charge it up and put your voltmeter on it. '20' should be correct.

    if it read close to 13 volts, discoonect the 12v battery and try starting the car with the booster.

    very unlikely that the 12v is original. in 15 years, you could be on the 3rd or 4th.

    there is a date code on the top
     
  11. edthefox5

    edthefox5 Senior Member

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    Better yet put your voltmeter across the charger and see what it reads.
    Get familiar with your vm you seem to have no confidence at all which is not good when messing around with the Prius 12 volt system.

    a selectable cheapo multimeter is a very poor choice for a rookie spend a little more get a fluke that has no settings it’s either AC or dc.

    Because if you own a g2 your gonna need it.
     
  12. Tynyyn

    Tynyyn Junior Member

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    I like you Ed. No BS and get straight to the point. Everybody has their expertise and I for sure am not the "go to" guy for electrics or Prius's. Sincerely I did not know there was such an animal as a volt meter as you've described. I'll check on it. I am crossing my fingers hoping and praying that the answer to my problems is a simple $200 new 12v battery. Maybe I'll hop down to my local Battery Outfitter and see what kind of replacement they recommend.,

    Thanks again for your advise.
     
    #12 Tynyyn, Jan 18, 2021
    Last edited by a moderator: Jan 20, 2021
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  13. fissshhh

    fissshhh Junior Member

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    Hi Tynyyn!

    My Gen 2 had exactly the same problem as yours, and I fitted a a replacement battery, (Cost about 60GBP), which solved the problem instantly. Hope the same goes for yours :)
     
  14. edthefox5

    edthefox5 Senior Member

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    Thank you very much for the kind words Ty. I will assist you as much as I can.

    you cannot go wrong with a new 12 volt battery on a g2. the best battery is the stock battery it’s a little more expensive but superior quality IMHO,
    Mine lasted 7 years even in this heat.

    I am on my second Optima yellow top there ok easy to get and have a solid 3 year warranty. Like $200 out the door minus the $30 coupon at the time,

    My first optima which was very popular then after my oem battery failed lasted exactly 2 years 11 months and 22 days. Autozone gave me a new battery, I’m still on that one and watch it closely by routine maintenance charges which tell you a lot of info. The most important being when that battery cannot reach a full 13.8 charge after many hours on the charger start watching it closely.

    having said that I have not bought a new 12 volt battery in 6 years there may be better choices so I encourage responses.

    as far as fluke voltmeters please go on eBay and search Fluke Dvm. There will be thousands of choices,
    Spend $100 on a new one it will last for years and years.it only has one setting for a and dc.
     
  15. Tynyyn

    Tynyyn Junior Member

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    Oh, the hair pulling continues..........

    So I went to Oreillys and bought a brand new AMG battery. Installed it and while standing at the hatch, instantly the lights on the dashboard lit up. By lights I mean the Brake light, seat belt, door open, hatch open, check engine light, ((!)), ABS and slippery when icy. And the display turned on. Plus there is a slight beeping coming from the passengers side of the dash. Hmmmm.....

    So I get into the drivers seat and THEN put in my key fob. All the dash lights stay on yet the car does not turn on, nor will the gear selector register if it is in drive or reverse. It does show PARK. So I try to turn the car off yet all of the lights stay on and the key fob will not extract.

    Thus the hair pulling part of my story.

    It has been a very long day of pouring concrete and finishing it and the last thing I wanted to do was still try and fix a wonky Prius. Fellows, have you got any suggestions on what the problem might be this time?
     
  16. bisco

    bisco cookie crumbler

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    might be a bad mfd, are you getting the 'ready' light? power button green?

    have you got a volt meter yet?
     
  17. qmanqman

    qmanqman Member

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  18. edthefox5

    edthefox5 Senior Member

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    The first time you install a new 12 volt battery and go to start the car it willlight up all lights and freak you out. All 12 volt circuits went offline when the battery was pulled and the car freaks because of it.

    Just let it sit for a bit and try to start it again it should start right up.

    if not measure the the 12 volts at the front jump point. Should be at least
    12.4 to 12.6.

    then measure directly across the battery itself. There should not be more than a .5. Or half a volt difference. There’s 8 connections and a long heavy duty cable from the battery to the front jump post so there’s about a half volt drop
    There.

    do not be surprised it the battery is low many a poster has bought a new battery only to find it was sitting on the shelf a long time and was never tested or charged before you bought it and went low sitting there.
    Especially if you see the guy take it right off the rack.

    next time you go to buy a battery and the counter guy says here you go it’s all charged up say great that’s nice then whip out your NEW FLUKE lol
    And test it on the counter.
     
  19. edthefox5

    edthefox5 Senior Member

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    I checked on Amazon get a fluke 15B voltmeter brand new nice meter you will own that one your entire life. On a g2 it will pay for itself first time you use it.

    $125.
     
  20. Tynyyn

    Tynyyn Junior Member

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    I finally fixed the problem. I pulled the 12v battery and went down to Oreillys. Two hundred bucks and change and out the door with a new battery. I installed it and everything went back to normal. A bad battery caused all of my angst. The date on the battery was 8-23-07. Yea, that is a very old battery and it kept chugging away until I began taking very short trips down to my work site. But now all that is wonky is a maintenance light which I can make go away with a scan tool.

    To all whom added knowledge to myself about how to fix the Prius, I appreciate all of your help. It is a wonder how lack of electricity can make these cars do the weirdest dashboard light dances.
     
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