Results 1 to 5 of 5

Thread: Battery Warning Light Issue Resolved

  1. #1
    Join Date
    Aug 2003
    Location
    Detroit, Michigan
    Age
    65
    Posts
    554

    Battery Warning Light Issue Resolved

    Even though it is embarrassing to admit how long it took me to catch on to the problem here, I thought I would document it, in hopes that it might help someone else.

    My son drove this Marauder one day, then drove it home for lunch. On his way to the house, the battery warning light had come on. So he parked it and took another car back to work.

    When I got home, the battery voltage was reading in the high 11s. But it would crank, so I started it up. Even revving the engine up did not kick the alternator on, at least as evidenced by the voltage reading, which stayed in the 11s.

    I happened to have a new alternator in my stash of Marauder parts, so I swapped that one in. Now when I revved the engine, the voltage across the battery was about 14 volts. Great, all fixed, I thought.

    So, I didn't want the alternator to have to charge the battery back up, so I removed the negative terminal and charged the battery with my plug-in charger. Just after taking the charger off, I was at about 13 volts across the battery. So I hooked up the negative terminal and went to start the engine. Nothing. No headlights. Not even any "dome" light. Just nothing.

    I scratched my head, undid the negative terminal, then put it back on, tightening it a bit tighter. Now the lights all worked and the car started right up. But after it had run for about 30 seconds, the battery warning light came back on and stayed on. I was puzzled, and didn't feel very confident that the new alternator had addressed the root cause.

    On the weekend, I took the car to AutoZone where they tested the old alternator, as well as the battery, starter, and alternator in the car. Everything, even the old alternator, checked out as good.

    Then on Monday, the car was driven about a mile and parked back at home. The next time we tried to start it, we got nothing again. No cranking, no lighting. But the voltage across the battery was about 12.4 or 12.5 volts.

    Once again, I removed the negative terminal from the battery, and re-attached it, tightening it securely. Once again, everything worked. But in 30 to 45 seconds, the battery warning light came on again.

    (For those of you keen to guess, stop reading here and make your diagnosis. It's pretty obvious, actually. Answer is below.)





    So here was the cause: Corroded battery terminals and cables. Especially the inner surfaces of the cables which contact the terminals. I cleaned all the corrosion off, and now everything works properly. No more battery warning light. It runs better, too. Before, the engine seemed to be "breaking up" when getting on it hard. Now it is once again very smooth. Apparently, so little current was able to get through the corrosion at the terminal that the demand of the ignition system overpowered the reduced capacity of the electrical system.

    The only thing that pisses me off is that I should have cleaned the terminals and cables when I first got the "no lights" condition just after charging it.
    Yours truly,
    Meteorite - Royal Oak, Michigan

    2003 300A - Black VIN = xxxxxxxxxxx600051 *** Build Date = 3/13/2002
    Best e.t. -- 12.31 @ 111.5 mph *** Now with: Trilogy #220, Alternative Auto Performance Tune + 4.10 Gears +SW headers + Metco control arms + Addco front and rear sta-bars + Dynotech Metal Matrix Driveshaft + Weldcraft widened wheels & MT drag radials.

    2003 300B - Blue

    And now ... 2003 Black (Trilogy #58)

    1962 Mercury Meteor & 1963 Mercury Meteor

  2. #2
    Join Date
    Jan 2004
    Location
    Somewhere in the N.C. Triangle
    Age
    68
    Posts
    26,250
    Check the negative cable(s) for resistance. I've seen corrosion inside the cables.
    “When you can’t make them see the light, make them feel the heat.”
    Ronald Regan

    "The only way to deal with the Islamic State - these blood thirsty, blood-drunken, terrorists -
    is to kill them, keep on killing them, until you kill the last one, then you kill his pet goat."

    Lt. Colonel Ralph Peters

    “Be polite, be professional, but have a plan to kill everybody you meet.”
    "I come in peace. I didn't bring artillery. But I'm pleading with you, with tears in my eyes, if you **** with me, I'll kill you all"
    General James Mattis




  3. #3
    Join Date
    Aug 2003
    Location
    Detroit, Michigan
    Age
    65
    Posts
    554
    Quote Originally Posted by fastblackmerc View Post
    Check the negative cable(s) for resistance. I've seen corrosion inside the cables.
    Good point.
    Yours truly,
    Meteorite - Royal Oak, Michigan

    2003 300A - Black VIN = xxxxxxxxxxx600051 *** Build Date = 3/13/2002
    Best e.t. -- 12.31 @ 111.5 mph *** Now with: Trilogy #220, Alternative Auto Performance Tune + 4.10 Gears +SW headers + Metco control arms + Addco front and rear sta-bars + Dynotech Metal Matrix Driveshaft + Weldcraft widened wheels & MT drag radials.

    2003 300B - Blue

    And now ... 2003 Black (Trilogy #58)

    1962 Mercury Meteor & 1963 Mercury Meteor

  4. #4
    Join Date
    Oct 2014
    Location
    Charlotte, NC
    Age
    67
    Posts
    1,281

    Arrow

    Quote Originally Posted by Meteorite View Post
    Even though it is embarrassing to admit how long it took me to catch on to the problem here, I thought I would document it, in hopes that it might help someone else.
    Thanks for this. It always pays the check the simplest, most obvious possibilities first. Like many, I'm guilty of starting at the 'wrong end' first. The school of 'hard knocks' can be an excellent teacher.

    Similar situation with my son-in-law just a few weeks back with his Expedition. CEL and mis-fire quickly progressed into a 'no start' with the vehicle completely dead. Battery was good, clamps needed cleaning and tightening. CEL was due to a malfunctioning COP - replaced all eight due to the mileage of the vehicle and it's cheaper to buy a complete set. 5.4L 3 valver back to ripping LOL!!!
    Current Garage:

    2005 Mustang GT Premium
    2019 Ranger Lariat Super Crewcab 4WD
    2015 Triumph Trophy SE



    “You've gotta dance like there's nobody watching,
    Love like you'll never be hurt,
    Sing like there's nobody listening,
    And live like it's heaven on earth.”
    William W. Purkey

  5. #5
    Join Date
    Sep 2002
    Location
    Cape Cod, MA
    Posts
    13,676
    Had a few electrical gremlins on my 2000 GMQ...headlights would dim when brakes applied, blinkers would experience random hyper-flash, voltage would fluctuate from 13.7 to 11.8 while driving...

    Turned out to be the cables had corroded inside the old-school "lump of lead" clamps I had installed a few years before. Couldn't see it until they were taken apart. Replaced them with new-style "band" clamps and all electrical problems disappeared. As was mentioned earlier, sometimes it's the simple things.
    The Blackbird
    Trilogy #61
    Driveway Queen

    The Spruce Goose
    2004 Grand Marquis LS Limited Edition
    Daily Driver

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Battery Charging Issue
    By ledzilla in forum The Lounge
    Replies: 2
    Last Post: 08-09-2016, 06:11 AM
  2. New Battery and Alternator - Battery Light Still On
    By blackf0rk in forum Shop Talk
    Replies: 62
    Last Post: 06-21-2010, 10:07 AM
  3. Odd battery issue: need help!
    By FiveO in forum Shop Talk
    Replies: 6
    Last Post: 07-10-2009, 12:17 PM
  4. Cruztaker's spoiler issue resolved
    By CRUZTAKER in forum Community Discussion
    Replies: 21
    Last Post: 01-21-2004, 09:03 PM
  5. Brake light flickering problem resolved, I think
    By TripleTransAm in forum Steering, Suspension & Brakes
    Replies: 4
    Last Post: 10-24-2003, 10:13 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •