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91 318is - where is the ABS relay? (dash light on)

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    91 318is - where is the ABS relay? (dash light on)

    ABS light stuck on (comes on when key to on, stays on when engine started)

    I've read the threads everywhere and suspect my ABS relay is blown, but I can't find the thing. Looked above ABS computer and did't see it From the descriptions it's a metallic cover, but on the parts sites it's meant to look like this:



    For m20 cars it seems to be under the dash by the driver's (LHD) knees. Only relay I see under there is four prong and seems to be for the blinkers.

    91 318is build thread

    #2
    correction, the relay I do have under there is not for the blinkers, it's for the "seat belt timers"


    91 318is build thread

    Comment


      #3
      It's near the control unit that is above the knee bolster, next to the steering column.
      http://www.r3vlimited.com/board/showthread.php?t=107828
      @turbovarg
      '91 318is, M20B25, T3/T04E 60 trim (15psi), megasquirt, coilovers, Z3 rack, cold AC
      [b u i l d]
      [Car of the month: April 2018]

      0c8b7c9527af628a346878feb14bf757

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        #4
        Thanks - I'd read that thread and even found some of the missing pics with google cache. That spot is where I've been looking, without any luck. Per other photos the relay clips to the ABS computer - and my computer doesn't even have something to clip to.

        Even looked for the wire colors in the looms to see if I could trace them per this description:

        there is a bundle of 6 wires, 2 brown, one green, the rest read [sic].

        didn't see anything that matched up. I'll take some pics

        91 318is build thread

        Comment


          #5
          wiring shots:








          91 318is build thread

          Comment


            #6
            Ok...it's suddenly gone.

            I'd pulled the three relays on the firewall, the contacts on the two end ones were corroded, cleaned the contacts on those. I'd had an issue with the alternator not getting 12v to the exciter, repairing that as I did last night could have fixed the ABS light.

            Finally, I'd re-bled the brakes today. They'd been completely replaced since the last time the car was driven - 7 series master cyl, new brake hard lines, braided brake and clutch lines, calipers rebuilt, ABS sensors pulled and cleaned when the wheel bearings were changed.

            Still not sure where the ABS relay is, but will remain happily ignorant for now.

            91 318is build thread

            Comment


              #7
              It appears there is no overvoltage protection relay in our cars. http://www.realoem.com/bmw/enUS/show...diagId=34_0161
              vs an earlier 325...
              http://www.realoem.com/bmw/enUS/show...diagId=34_0161
              Sorry for the bad info before.
              @turbovarg
              '91 318is, M20B25, T3/T04E 60 trim (15psi), megasquirt, coilovers, Z3 rack, cold AC
              [b u i l d]
              [Car of the month: April 2018]

              0c8b7c9527af628a346878feb14bf757

              Comment


                #8
                At some point the overvoltage relay was moved to underneath the cover of the ABS pump itself.

                Comment


                  #9
                  Originally posted by cunninglinguist View Post
                  At some point the overvoltage relay was moved to underneath the cover of the ABS pump itself.
                  This isn't reflected in the realoem links above, the later pump has a different part number for one of the relays, but the only difference is an extra pin with what appears to be a flyback diode on the supply leg of the relay.

                  Early:


                  Late:
                  @turbovarg
                  '91 318is, M20B25, T3/T04E 60 trim (15psi), megasquirt, coilovers, Z3 rack, cold AC
                  [b u i l d]
                  [Car of the month: April 2018]

                  0c8b7c9527af628a346878feb14bf757

                  Comment


                    #10
                    ABS relay s/b one of the two orange relays under cover at cowl. White is main, other is fuel pump. Ck your sensors at each wheel... disconnect 3 (front@wheel wells, rear@under seat) ignition on and roll car. reconnect first and go next in sequence (1, 2, 3, 4 no order) until abs light kicks on. That will be the bad one :)
                    Instructor, NASA-MA. Chump Racer

                    Comment


                      #11
                      Resurrecting this thread. 1990 E30 325i Vert. ABS light on. I can’t locate the relay. It’s not under the dash next to steering column. I understand the later models did not have the relay under the dash. Anybody know where it’s located. If not the relay, why else would the abs light be illuminated?

                      Comment


                        #12
                        Does the light come on instantly or once you start moving?

                        Comment


                          #13
                          The two relays are under the abs cover. They are not under dash. 91 318
                          NASA
                          BMWCCA member
                          PCA member 25yrs




                          1991 318IS slick top
                          1997 M3 sedan
                          2001 325CI DD

                          “whoever turns the wheel the least, wins"

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