After grounding out my alternator lead battery wire, I had to replace the 120 amp fuse that connects to the alternator. After replacing the fuse the car started up fine but upon driving home and shutting off the vehicle and trying to restart it I found that it didn't crank anymore. I open the hood to find my 120 amp fuse that I had just bought has blown once again. This is obviously a failure in my rewiring the battery lead on the alternator, but for the life of me I can't figure out where I went wrong. My contacts don't ground and I cleaned all surfaces, yet I still blow a fuse every time. Can somebody please help?

  • 1
    What's the car? Are you sure the wire isn't rubbing anywhere? Try doing a voltage drop test on the wire to check for short to ground.
    – Ben
    Aug 3, 2016 at 23:27
  • Do you think you could add some more detail about what's going on here? I'm having trouble visualizing the transition from your previous question mechanics.stackexchange.com/q/33765/9884 to this one. Did you repair the alternator post and restore the correct connections... ? Is this a different question? What is the current state of this vehicle?
    – Jason C
    Aug 4, 2016 at 0:38
  • 1
    Have the alternator tested.
    – Moab
    Aug 4, 2016 at 1:06
  • @JasonC this is actually a branch off of my old question. After realizing the mistake I had made I found that I had blown my alternator fuse. Thinking that all I had to do was reconnect the wire to the Post was a mistake that led to this question. After I had replaced the fuse the first time and reconnected the wire to the Post the broken 1. That's where this question comes in Aug 4, 2016 at 5:36
  • How did you fix the broken post?
    – HandyHowie
    Aug 4, 2016 at 7:17

2 Answers 2


It turns out that I kept blowing my fuse because of the way I had been connecting the wire to the b+ post on the alternator. Due to the small amount of threaded post I had left, I tried to sit the wire directly onto (and through the post) the alternator. I covered the bare metal under it with rubber to ensure that I wouldn't ground, then screwed a nut and washer ON TOP of the wire, instead of the normal setup which is nut, wire, nut+washer (broken post). For some reason that setup was sending too much current(?) through the wire and would end up blowing the fuse, which would explain the initial successful start with the blown fuse on the retry. I ended up sitting the wire on the nut+washer, with the latter acting as a terminal of some sort... Like how the battery wires sit on a terminal and not the actual battery posts, and temporarily strapped the wire to the nut with an elastic band to keep it in contact with the makeshift terminal.. Success!

  • 1
    It is good that you have got a fix, however after reading how you have fixed it, I would be very concerned about the possibility of an electrical fire. You could find that the connection you have made has a relatively high resistance and if a lot of current is drawn from the alternator, the connection could start getting very hot. I wouldn't leave it like that if I were you.
    – HandyHowie
    Aug 4, 2016 at 12:41

I have a 2002 Mitsubishi lancer, what kept occurring was a drainage in my battery. At first I couldn't figure out why -- I got my alternator checked & my battery: both were good.

Long story short CHECK YOUR POSITIVE TERMINAL FUSE. That was the problem for me. (It was also showing a battery and brake light - another indication why I thought it was my alternator, but it was that fuse -- don't be fooled!!) I went to O-Reilly & Auto Zone and they both said they don't carry it, but O'Reilly actually does(!). Just show them the image & be very specific

enter image description here

  • Welcome to Motor Vehicle Maintenance & Repair!
    – Cullub
    Aug 28, 2018 at 2:59

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .