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  • 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
    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

    Comment


    • #3
      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

      Comment


      • #4
        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.

        Comment


        • #5
          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

          Comment


          • #6
            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

            Comment


            • #7
              everything leads back to faulty voltage regulator

              Comment


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

                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

                Comment


                • #9
                  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

                  Comment


                  • #10
                    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

                    Comment


                    • #11
                      from the 95 shop manual sympton chart for overcharging

                      - voltage drop in 'A' circuit30 (R)
                      - voltage drop in 'I', Circuit 15 (GN/BK)
                      - poor ground
                      - voltage regulator
                      - generator

                      test steps

                      A1 - check 'A' circuit - ignition to run - measure voltage between (+) battery post and test point A on voltage regulator - is drop less than 0.25V -- if yes go to A2, if no service excess voltage drop in circuit 30 (R). check fuse and connectors in circuit 30 (R) and service as required

                      A2 - check 'I' circuit - back probe generator connector to measure voltage at wiring harness 'I' terminal, circuit 15 (GN/BK), is voltage less then 1V -- if yes go to A3, if no service high resistance in circuit 15 (GN/BK)

                      A3 - check grounds - check for poor grounds between voltage regulator and generator, generator and engine, engine and battery, are all grounds clean and tight -- if yes go to A4, if no clean and service grounds as required

                      A4 - check for field circuit drain - turn ignition to off - measure voltage at test point 'F' on voltage regulator - is voltage at test point 'F' equal to battery voltage (ground voltmeter to case) -- if yes generator ok, replace voltage regulator, if no go to A5

                      A5 - check for grounded slip ring - remove generator from vehicle - remove voltage regulator from generator - measure resistance from each generator slip ring to the generator housing - is resistance less that 200 ohms -- if yes if grease or dirt has collected near slip ring, clean and recheck, if still less then 200 ohms replace generator, if no replace votlage regulator
                      - 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

                      Comment


                      • #12
                        if indicator lamp does not come on

                        open/high resistance in 'I', Circuit 15 (GN/BK)
                        burned out bulb
                        poor ground
                        'S', Circuit 63 (W) shorted to B+
                        voltage regulator
                        generator
                        - 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

                        Comment


                        • #13
                          Originally posted by 95_Mystique View Post
                          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.
                          Check the condition of both battery cables; badly corroded connections and/or the cable itself can do this due to the high resistance created in the path between the alternator and the battery.

                          I was working on a 2002 Pontiac Grand Prix SE recently and it was charging at ~ 16.5 volts. The battery is a side-post design on this car. Disconnected both cables and found that the positive terminal on the cable was completely corroded as well as most of the cable strands inside the plastic insulation. The battery terminal itself was fine. Cleaning off the corrosion on the connection portion of the cable fixed the problem but I ended-up replacing the cable to ensure a more lasting fix. The root cause of all the corrosion was the rubber insulation at the cable end had cracked open and at a later date, somebody flushed the cooling system. The radiator cap is right by the positive batter cable and antifreeze had burped-out and worked its way into the postive battery cable. Check for any splits in the insulation along the whole length of your positive and negative cables. If there is any of that plastic accordion-like wrapping on your cables, you will have to extract the cable from this to properly do the inspection.

                          The same issue should also be applied to the main power lead at the alternator and any ground straps connecting the motor to the body/frame.
                          Mr. Spindlelegs
                          1999 Black SVT #1658 of 2760
                          2004 Volkwagen Golf TDI

                          Comment


                          • #14
                            Well, i have it charging correctly now, but now the battery light stays on. i was wrong, it does work, i've just never really noticed it cuz it's never come on while driving. Cant figure out why it says on. The car is charging at 14.5 vots.
                            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

                            Comment


                            • #15
                              Weird thing happend to me today,my battery light came on today but it was flickering like a strobe and i also have pulleys grinding,so i jacked my car up and wiggled the one wire clip,no luck i went to the drive through at burgur king and my pulleys were so loud i couldnt hear the lady so i shut the car off and it wouldnt start back up it just went waaaaa it didnt even sound like it was turning over so i pushed it out of the drive through and it started to roll down a hill had to jump in lol.....then i got it to start and the pulley sounded like gun shots real loud and it went away and now it whistles quietly and the alternator light went off and hasnt came back on it very odd its a brand new non rebuilt alternator also i HATE MY svt right now lol

                              Comment

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