Super Cheap Auto Castrol Edge Michelin Go Fast Bits Shannons Insurance Haltech Ryobi Century Batteries WD-40 KYB NTK NGK Spark Plugs Whiteline


No announcement yet.

Subaru Legacy kills battery

  • Filter
  • Time
  • Show
Clear All
new posts

  • Subaru Legacy kills battery

    Hey guys,

    Anyone know how much a Subaru Legacy BE9 should draw when off and when the key is at Acc?
    Mine draws 0.9A when off and 11.4A (sometimes 12.7A) when the ignition is at Acc.
    If I leave the key at Acc the battery dies within an hour so.

    I have a brand new 649 battery installed for reference.

  • #2
    It does sound like a ground leak; might be overdue a new coating of dielectric grease in the engine bay plugs.

    Since you clearly know how to use a multimeter to measure amps; start pulling fuses 1 by 1, and using the multimeter as the link.
    Find out which circuit is the culprit.
    Last edited by Master_Scythe; 25-06-2021, 08:33 PM.


    • #3
      So this is what I found when I remove the following fuses in the engine bay.

      Meter SRS lamp 11A to 4.5A
      SBF2 11A to 8.3A
      SBF4 11A to 0.36A

      No idea what the SBF fuses control. Can't find any info on them in the service manual.

      Master_Scythe I did this test before your reply. I put the multimeter between the battery positive and the positive cable of the car.
      Last edited by Svenironhand; 28-06-2021, 11:01 PM.


      • #4
        You can further narrow it down by using the multimeter IN the fuse box.
        As for what they go to SBF4 is an 'accessory' fuse, that controls lots of power to little things when the key is in the ACC position. While you have the car entirely OFF, it shouldn't be doing squat.

        I'd assume a faulty ignition switch in the key barrel; HOWEVER....
        Considering those fuses..... Have you tried starting the car without the cluster connected?
        Failed clusters are super common, they corrode and earth out all the time.

        Keep in mind your alternator won't work without the cluster in; so you might want a battery charger if it DOES help. Subaru in their infinite wisdom runs the 'battery light' in the cluster as part of the alternator relay... We went through 4 alternators before we learned this a few years back.

        Popped down to the local Harley shop and got a T5 bulb rated for motorcycle use; that bad boy won't be blowing any time soon.


        • #5
          So got home early today so I did a bit of poking around and did what Master_Scythe suggested.

          This is what I found when the ignition is in the Acc position:

          SBF1 8A (I assume this is the main power fuse?)
          SBF2 0A
          SBF3 0A
          SBF4 3.6A

          SBF5 1.57A also there is a strange buzzing coming from the car when this fuse is removed

          Other SBF fuses 0A

          Meter (SRS Lamp) 0.9A also causes a buzzing sound but only lasts 3 seconds

          Clock/Room 0.63A

          So it seems theres +- 6A unaccounted for.

          My plan is to put dielectric grease on the engine bay connectors and such. Also go through the car and see if there is any more shoddy diy wiring in the car. (The previous owner really made a mess of the car).


          • #6
            Also the car draws 0.06A to 0.09A when its locked. (Which I know is fine)


            • #7
              SBF1 in most subarus is the main fuse and should be a 30A under hood; must be different in the BE9.

              Long shot; monitor the SBF1 fuse, and pull the ABS fuse..... Just a hunch.


              • #8
                Cool thanks bro. Will do