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Hooked up battery backwards... Accessories work but blowing fuse when trying to crank

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  • Hooked up battery backwards... Accessories work but blowing fuse when trying to crank

    2000 SAN - PCM GT40 Ford 5.8L

    In a rush today, I hooked up battery backwards. It blew the the 20 amp inline fuse that runs directly from my battery to the control box under the dash. I replaced the fuse and now have power to everything (blower, lights, heater fan, bilge, etc.) but the boat won't turn over.

    Using the keypad, I can turn the ignition on. The fuel pumps turn on and it appears ready to crank. However, when I push (and release) the start button to crank, nothing happens. When I push and hold the start button, I blow the 20 amp inline fuse directly connected to my battery again. Under the dash, I hear the start button click (once ) when pushing in, again (click) at release. I don't hear anything from the engine.

    Areas I've looked at so far -
    • Cleaned terminals / grounds
    • 12 volts on both sides of the 60 amp breaker
    • 12 volts at starter solenoid
    • 12 volts at starter
    • Replaced starter solenoid
    I'm not familiar with the breaker normal operation as have never checked them before. But the 12.5 and 15 amp breakers have a little play in them when i push them The 60 amp on this engine is frozen solid (no movement at all). Tried rocking up and down, but that didn't work. However, there is power to both sides.

    Help please.

  • #2
    My guess is you have something similar to what happened with mine. It too did the same thing, blew the 20A dash fuse when you tried to start. The problem is this: you're trying to draw all the power through the 20A dash lead to turn over the starter. Mine turned out to be a crappy positive battery cable back to the starter, but it could really be anything in the positive chain (or maybe even the negative) to the engine that's at fault.

    Go get a 10 pack of 20A fuses, and start ohming stuff out. You'll find an open in your batt to engine lead somewhere.
    2001 Ski Nautique / 2007 SV211 TE