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Thread: Alternator is overcharging. HELP

  1. #1
    Join Date
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    Default Alternator is overcharging. HELP

    I've now replaced the alternator 3 times in the past 12 hours cuz the test for the regulator is saying the regulator is bad. It keeps charging at 15.5-16.5 volts. Before, my issue is that it wouldnt charge at idle. Ever since replacing the alternator, it's been overcharging. all of the fuses are good from what i can tell, and all of my connections are good. At work, i'm not able to get a wiring diagram for a 2000 CSVT, or a pic of the fuse block under the hood with the fuses labled. My owners manual is from a 99 and its totally differen.


    Help! I'm taking it on a trip in 4 days.
    00 Contour SVT #1914 BLK/PT 2.5 Full bolt on/torsen
    00 SVT Contour # 0889
    98 Contour SVT #2147 Silfro/mnb. Former ElKy car! Sold
    00 Contour SVT #0157 BLK/PT parted out
    95 Mystique GS

  2. #2
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    cambridge,On
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    heres a wiring diagram of the charging system for a 2000 svt, it shows the fuses you need to look at



    Od5 is saying if your system is overcharging, do a voltage regulator test.

    Step 1 - turn ignition switch to RUN position.
    Step 2 - measure voltage between generator terminal "F" and ground.
    Step 3 - if battery voltage is present,replace voltage reguator.
    Step 4 - if battery voltage is not present, repair short in Black wire between battery and generator
    Step 5 - retest system
    heres a figure where "f" is


    hope this helps you

  3. #3
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    ok, when nothing is plugged in, i dont have any kind of short/connection between ANY of the wires, which is good. All of the wires have a connection from one end to the other, which is also good. As far as i know, both 7.5amp fuses are good. I even tried swapping them out, still no change. The 175amp alt fuse has to be good, seeing as how i have continuity between either side of it. It doesnt make sense to me why i would get 2 bad alternators with bad regulators, then throw my old alt on and instead of not charging, it begins to overcharge.

    Thanks for the wiring diagram.
    00 Contour SVT #1914 BLK/PT 2.5 Full bolt on/torsen
    00 SVT Contour # 0889
    98 Contour SVT #2147 Silfro/mnb. Former ElKy car! Sold
    00 Contour SVT #0157 BLK/PT parted out
    95 Mystique GS

  4. #4
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    Oct 2011
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    cambridge,On
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    no problem . one more thing hows your Accessory drive belt and tensioner?

    if there good , then my last thought would be a bad cell in the battery . just threw one you have laying around(hopefully you do) and give it a try.

    my old svt had one bad cell and it made the alt overcharge, trying to recharge the battery.

  5. #5
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    The battery is new, and i tried a new battery as well and that didnt work at all. The belt and tensioner look fine as well. Would a battery light on the dash not working affect it?

    Also, battery voltage was always present at F terminal screw.
    00 Contour SVT #1914 BLK/PT 2.5 Full bolt on/torsen
    00 SVT Contour # 0889
    98 Contour SVT #2147 Silfro/mnb. Former ElKy car! Sold
    00 Contour SVT #0157 BLK/PT parted out
    95 Mystique GS

  6. #6
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    Location
    Gales Ferry, CT
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    yes, if the dash light isn't working the alternator will not charge.
    - 12 Focus SE
    - 95 Mystique LS <-sold
    - 99 Contour SE Sport <- traded in 2/13
    - 99 Contour SeVT <- 3L/NPG Turbo
    - 2k Contour SVT - #2137

  7. #7
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    everything leads back to faulty voltage regulator

  8. #8
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    Quote Originally Posted by BrApple View Post
    yes, if the dash light isn't working the alternator will not charge.
    Will it make it overcharge?

    Quote Originally Posted by marieiro View Post
    everything leads back to faulty voltage regulator
    Thats what i'm thinking. I'm going to Ford tomorrow to get a new alternator.
    00 Contour SVT #1914 BLK/PT 2.5 Full bolt on/torsen
    00 SVT Contour # 0889
    98 Contour SVT #2147 Silfro/mnb. Former ElKy car! Sold
    00 Contour SVT #0157 BLK/PT parted out
    95 Mystique GS

  9. #9
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    Aug 2010
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    Phoenix, Arizona
    Posts
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    I had this same problem and long story short I removed the mega fuse cleaned the connections with emery cloth and the problem was solved. I would advise you do that. I don't know how that worked. I didn't test it but maybe do a voltage drop across the positive cable and see what you get
    99 Mercury Mystique LSVT Port matched 3L with some goodies
    74 Maverick 351 Windsor building 347 stroker
    86 Porsche 944 Turbo

  10. #10
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    Mar 2011
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    DALLAS,TEXAS
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    Mine was overcharging and making my headlights pulsate i bought a 100% new alternator and it solved all my problems, if everything else is fine its probably the reman alternators i heard of people putting in 8 different alternators till they found a good reman

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