Electrical Gurus, a little help, please

Discussion in 'The Garage' started by jms, Apr 4, 2005.

  1. jms

    jms 1/2 ton status Author

    Jan 24, 2001
    Likes Received:
    '85 K5, 105A Wrangler NW alternator, 1500 mile road trip, two power washes, including one under the hood. Now my alternator makes a whining noise.

    Truck is shut down, key out of IGN, whine comes definitively from the alternator. Whine goes away when I disconnect the ground at the battery, or when I disconnect the flat-blade connector at the ALT. Checked the two connectors coming to the ALT, one has power (red wire), the other doesn't.

    If I'm not mistaken: the red wire ought to be the ALT exciter wire, the white is the voltage sensing wire. IIRC, the red wire should be 12V IGN ON, but not a constantly hot wire?

    I don't think constant power to ALT is good, so I'll check the ignition switch next. Any input is greatly appreciate, thanks, michael.

    Edit: found out the red wire is the sensing wire and should be hot, still no idea what the whine is, I'm sending the ALT back to WranglerNW to have it checked out; truck is down for scheduled post-EJS maintenance anyways...
    Last edited: Apr 4, 2005

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