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04 Cobra electrical short

Discussion in 'Engine/Tuning' started by 04 Black Betty, Sep 8, 2019.

  1. 04 Black Betty

    04 Black Betty New Member Established Member

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    After reading numerous threads on various electrical problems with different members, I can’t seem to find one quite like mine. So here’s the problem. I have an unspecified amount of amps (It blew my 10 amp multimeter fuse) flowing through my negative cable running to my battery. It has fried one battery. The negative cable would be warm to the touch after only a few minutes.
    I have located the 40 amp fuse in the engine compartment that is for the pcm/cluster. I remove fuse, short goes away. I have checked all grounds, unplugged about everything (starter, alternator etc ) to try to isolate and also have unplugged The CCRM and PCM and still have the problem. I’m not sure where to turn next .
    Thanks for any and all help
    Eric
     
  2. me32

    me32 BEASTLY SHELBY GT500 TVS Moderator

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    Any modifications? I would definitely check all your grounds and check all your positive cables.
     
  3. 04 Black Betty

    04 Black Betty New Member Established Member

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    Yes. VMP. Lethal return system. Exhaust. I’ve unplugged the power from pumps and relays associated with fuel system. Also have checked cables. Pulled back wire covers to make sure there was no corrosion
     
  4. olympic

    olympic Well-Known Member Established Member

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    There's a module under the drivers side dash, above the fuse box, that sort of looks like a brain box for an alarm. I've heard this can cause a battery drain if it malfunctions. Worth a shot to disconnect it and see what happens.
     
  5. 04 Black Betty

    04 Black Betty New Member Established Member

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    Thanks Olympic I’ll take a look and see if that’s it
     
  6. BlckBox04

    BlckBox04 I am the liquor Established Member

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    where is this hot ground wire mounted for the alt?
     
  7. 04 Black Betty

    04 Black Betty New Member Established Member

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    Are you asking where the wire from the alternator is mounted ?
     
  8. BlckBox04

    BlckBox04 I am the liquor Established Member

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    the one that you're saying is getting hot, where is it grounded?
     
  9. 04 Black Betty

    04 Black Betty New Member Established Member

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    Gotcha. It’s mounted to the motor mount on drivers side
     
  10. hotcobra03

    hotcobra03 Well-Known Member Established Member

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    I would think if just ground wire is warm it has to be loose on other end

    I’m confused on how you say a short but didn’t say fuse keeps blowing
    But say wire is warm
     
  11. 04 Black Betty

    04 Black Betty New Member Established Member

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    Ground wire is tight to the motor mount that runs to negative side of battery. The 40amp fuse has never blown But when I remove the fuse and I hook up negative side cable to battery the arch goes away. When 40amp fuse is back in place the arch is back. When car is running. The negative side cable is very warm, almost immediately after car is started
     
  12. 04 Black Betty

    04 Black Betty New Member Established Member

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    Maybe short is not the correct term to use. I have current running through the negative side cable to battery
     
  13. slo984now

    slo984now AKA 01yellerCobra Established Member

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    Is this anytime the battery is connected or only when the engine is running? It might be worth picking up a current loop probe from Harbor Freight so you can see how much current is actually flowing. It wraps around the wire and cuts down the amount of current being sent to the DMM.
     
  14. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Premium Member Established Member

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    maybe I just didn't get it from the post - have you found a diagram detailing what goes to that 40amp fuse to try and further isolate it?
     
  15. 04 Black Betty

    04 Black Betty New Member Established Member

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    It’s when the battery is connected
     
  16. 04 Black Betty

    04 Black Betty New Member Established Member

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    No I have not. But trying to locate a diagram
     
  17. 04 Black Betty

    04 Black Betty New Member Established Member

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    Olympic I disconnected that box you referenced to with no luck
     
  18. hotcobra03

    hotcobra03 Well-Known Member Established Member

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  19. 04 Black Betty

    04 Black Betty New Member Established Member

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    I have not tried starting car with fuse out. Its fuse F1. 6 (PCM/Cluster) I was reading 14 volts at battery when car was running before I started diagnosing.
     
  20. hotcobra03

    hotcobra03 Well-Known Member Established Member

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    F1-6 powers half the inside fuse box
     

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