Help! Car completely died on the road. No power

Discussion in 'Mustang Chit Chat' started by theRedStorm, Apr 9, 2021.

  1. theRedStorm

    theRedStorm forum member

    144
    20
    So I recently replaced my alternator as the voltage regulator on my old one was dying. Did the swap and turn on the car. Everything ran great for a day or two. But today, I was gunning down the highway and BAM outta no where, complete power loss. No lights. No power steering, no signals. I managed to pull over. Now there was ZERO electrical power in the car. Like there isn't a battery connected. Oddly, my halo led rings were still on and functioning even tho my car could not get power no matter what. While on hold for a tow truck, I decided to take the ground cable off terminal to see if I can reset the car. Wait a few minutes and then reconnected everything. It still didn't work. I disconnected ground again, waited 10-12 minutes, and reconnected. Everything worked flawlessly. Drove the car back home no problems.

    When the car died, I mean it completely died. Like the gauges froze where there were and wouldn't move. Couldn't get the car to power up at ALL til I removed the negative terminal. All these issues
    Any idea what this could be? My guess would be bad ground. My LED halos were still working. Don't understand why those didn't completey die
     
  2. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Age:
    58
    2,948
    937
    A bad ground is most likely but also check all the red positive cable connections for looseness or corrosion to be sure there isn't another issue.
     
    theRedStorm likes this.
  3. RED09GT

    RED09GT Equal Opportunity Offender S197 Team Member

    2,477
    406
    Check the wiring of the halos for a short. If they operated and nothing else did, they are probably the issue.
     
    theRedStorm likes this.
  4. Juice

    Juice forum member

    2,991
    996
    Not really enougb info IMO to offer specific help.
    With that said, I dont know what would happen on these cars if the battery was disconnected while the car is running. I "could" cause what happened. So it "could" be one of the cables or batt terminals has a bad connection. And that would be an OPEN circuit, not a sbort.
    Where did you tap power from for the balos?
     
  5. LarryJM

    LarryJM forum member

    977
    143
    I had a bad alternator and my car did the same thing. It ran on the battery for about 2 hours and then just died. The battery was healthy so after sitting for 10 minutes it would start and run again for about 10 minutes and then die again. Actually did this several times. There is an amp hour rating for these batteries.
     
  6. jewc75

    jewc75 S197 Junkie S197 Team Member

    19,697
    846
    Juice, does the early s197's have a mega fuse? My 2012 does but i dont think i ever looked to see if my 08 had one.
     
  7. Juice

    Juice forum member

    2,991
    996
    Like a main fuse link? Not really sure on that.

    There is the heavy gauge 12v feed from the battery + to the BEC, and its all in the BEC from there. If there is anything, it would have to be that wire.
     
  8. jewc75

    jewc75 S197 Junkie S197 Team Member

    19,697
    846
    Mine is at the main positive wire to the battery.
     
  9. theRedStorm

    theRedStorm forum member

    144
    20
    I tapped into the turn signals for the halos and I have a wire with a fuse running from the bluetooth controller to the bolt that connected to the fuse box.
     
  10. theRedStorm

    theRedStorm forum member

    144
    20
    I recently replaced my alternator (stock that had a failing regulator) with a 2009/2010 denso Remy rebuilt one from Rockauto. Could it be I got a defective one?
    I am still using the stock power wire with no fuse. I don't know if I should have upgraded my power wire when I upgraded to the new alternator. Perhaps the stock 2005 wire can't handle the voltage a newer 2009/2010 alternator puts out and maybe I should upgrade that?


    Thank you all for the help!! I truly appreciate it :yeahrightangel:
     
  11. theRedStorm

    theRedStorm forum member

    144
    20
    20210411_204511.jpg 20210411_204059.jpg
     
  12. LarryJM

    LarryJM forum member

    977
    143
    On Roadkill, they purchased a new alternator and it was defective. Just wanted to point that out.
     
    theRedStorm likes this.
  13. theRedStorm

    theRedStorm forum member

    144
    20
    I did find this on the internet. I do believe the new alternator was a 3g upgrade Screenshot_20210412-052024_Firefox Focus.jpg
     
  14. theRedStorm

    theRedStorm forum member

    144
    20
    M
     
    Last edited: Apr 12, 2021
  15. theRedStorm

    theRedStorm forum member

    144
    20
    Giving an update.


    I installed new power and ground cables. Still didn't fix it. I was going through my fuseboxes and saw that some of SJB parts had corrosion on them. I am almost 100% sure it has to be this box. That would explain why I can get the turn back on after removing the ground cable for 5 mins or so after it completely dies. Power cable upgrade wasnt the issue tho
     
  16. stkjock

    stkjock ---- Madmin ---- Staff Member Administrator Super Moderator S197 Team Member

    39,507
    2,374
    check for water intrusion, notorious issue with these cars, front cowl drains get clogged.
     
    theRedStorm likes this.
  17. theRedStorm

    theRedStorm forum member

    144
    20
    20210421_151248.jpg 20210421_151243.jpg 20210421_135455.jpg i cleaned all the contacts and made sure no more corrosion was left. It wasn't as much as expected but definitely was there. Fingers crossed this fixes it
     
  18. theRedStorm

    theRedStorm forum member

    144
    20
    I added a 2 gauge power wire + dedicated ground incase of any power wire problems. 20210420_172609.jpg
     
  19. theRedStorm

    theRedStorm forum member

    144
    20
    Now I'm blown. So after cleaning contacts and connecting everything back up, I have Zero power. Nothing works at all. Volt meter reads 12.9V and 4 amps drawing. No short either.
    Could it be my SJB could have gone bad? I'm lost :angry1:

    Any way to test the SJB?
     
    Last edited: Apr 21, 2021
  20. Juice

    Juice forum member

    2,991
    996
    Plug in a "known good" unit is about all I can think of.
     
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.