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    Battery light/alternator instrument gauge

    Hi everyone.

    I'm rather new to the e30 scene and just experienced my first major issue. The car died on me while driving it the other day, I tested the battery charged it up car started just fine again so I figured it was the alternator. That was a pretty easy swap. Afterward I started it right up and drove a round a bit the car stranded me again. I started reading in the forums and it looks like it could have been the battery light. I opened up the dash and replaced it, but it's still not coming on when I turn the key, to make things even more bizarre it comes on real briefly when I shut the car off. I do not see any evidence of issues with the soldiers on the cluster board. That said my tach light started acting up, when I turn the lights on the tach light wasn't coming on but if I tap the gauges it comes right on, it's not the bulb.

    Currently the car is not charging the battery at all, so there definitely something still wrong. Any help is much appreciated.

    Video of the gauge behavior.
    Last edited by kchase731; 07-15-2016, 05:11 PM.

    #2
    Something very wrong with your cluster, that could cause the alternator won't charge the battery.
    If I were you I'd find another cluster to try.

    Comment


      #3
      what year is it?
      Late model clusters have a resistor wired in to prevent the "no charging battery light out" issue.
      RHD OBD2 M50b25 turbo build thread:
      http://www.r3vlimited.com/board/showthread.php?t=384800

      Comment


        #4
        That's a late model cluster. Battery light should be on with key on. You should have a bypass resistor in parallel with the batt bulb. Bmw updated this in late 85. The green LED's should not be on with the car running. Try another cluster to help troubleshoot.
        "I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj

        85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
        88 M3 - LACHSSILBER/SCHWARZE
        89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
        91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER

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          #5
          It's an 89. I just purchased a cluster board, that's been remanufactured. The gauges and everything all work so I'm hoping I can swap the board and it will be ok.

          Does anyone think I also need to change the Si board?


          Sent from my iPhone using Tapatalk

          Comment


            #6
            Originally posted by kchase731 View Post

            Does anyone think I also need to change the Si board?


            Sent from my iPhone using Tapatalk
            Swap the cluster board to test it first, if everything work why change more part. SI board is not cheap.

            Comment


              #7
              New si board new cluster board still nothing. Does anyone know how to test the voltage at the alternator while it's running?


              Sent from my iPad using Tapatalk

              Comment


                #8
                Originally posted by kchase731 View Post
                New si board new cluster board still nothing. Does anyone know how to test the voltage at the alternator while it's running?


                Sent from my iPad using Tapatalk
                Place a volt meter anywhere in the system (cigarette socket is a good one) and check to make sure that the alternator can put out at least 13.6 V.

                Comment


                  #9
                  I'm definitely not getting 13.6 v at the battery or at any other electronics which is why I wanted to test it at the alternator. I'm just not sure of a safe way to check the voltage at the alternator while the car is running


                  Sent from my iPhone using Tapatalk

                  Comment


                    #10
                    It's the amperage that kills you, not the voltage. Sticking the meter into the cigarette socket while the car is running won't kill you. You can test at the alternator if you want...positive goes to the post for the big red cable and negative goes to the chassis.

                    Comment


                      #11
                      So I'm getting 0 at the alternator. I checked the voltage regulator and the brushes are long and new. It's a new alternator and the belt is definitely tight and spinning it so bad alternator?


                      Sent from my iPhone using Tapatalk

                      Comment


                        #12
                        Yeah, it does sound like your alternator is dead and you are running off your battery.

                        Comment


                          #13
                          Have you checked the wiring harness to the alternator? You got the correct alternator with solid mounts right? Assuming you have a 325i. Take a pic of the alternator.
                          "I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj

                          85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
                          88 M3 - LACHSSILBER/SCHWARZE
                          89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
                          91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER

                          Comment


                            #14
                            If you leave the car idling, does it shut off within a few minutes and then the batter is completely dead? If so, that could be a telling sign of alternator failure. Agreed with the guys about putting the volt meter into the cigarette socket to get a reading. If that concerns you, then you could put the meter on the terminals and have someone else (a helper of sorts) turn on the air conditioner, light, etc. You should see a spike in voltage once these things are turned on and then the voltage settle back down around 12V.
                            sigpic

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                              #15
                              Originally posted by kchase731 View Post
                              So I'm getting 0 at the alternator. I checked the voltage regulator and the brushes are long and new. It's a new alternator and the belt is definitely tight and spinning it so bad alternator?


                              Sent from my iPhone using Tapatalk
                              As in "0 Volts" at the alternator terminal?
                              If this is true than your alternator is not connected to your electrical system.
                              You should be able to measure at least battery voltage at the output terminal.
                              1988 325 non-letter Seta "Bronzit"
                              1991 325ic "Laguna Green" (Sold)
                              1993 325i "Laguna Green/Silver" (Sold)
                              1998 528i "Artic Silver" m-sport(totalled by drunk driver)
                              2000 528i Titansilber/gray m-sport
                              2000 528i Titansilber/black m-sport(sold)
                              2001 525i Anthracite m-sport(sold)
                              2013 750i Black/Black m-sport "Beast"

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