Results 1 to 7 of 7

Thread: Battery light when i am driving and the heat is on

  1. #1
    Join Date
    May 2008
    Location
    Allentown, PA
    Posts
    9
    My Cars
    2004 Bmw 325i

    Battery light when i am driving and the heat is on

    OK i got a weird issue. Whenever i drive and turn the heat on my battery light comes on. when i turn the heat off then the light goes off after a minute. I can run the AC and no light. I originally thought it could be the alternator but i tested it and was getting 14v.

    Did some research and i see this article about the final stage unit/blower motor resistor? Only thing is i dont think i get speratic fan speeds, i only get the battery light. Do you think the resistor is the issue?

    I did get a Optima yellow top battery a while ago but that pretty much all i changed on the car

    Help please
    Last edited by dydigital; 10-22-2008 at 03:31 PM.

  2. #2
    Join Date
    May 2008
    Location
    Allentown, PA
    Posts
    9
    My Cars
    2004 Bmw 325i
    Bump

  3. #3
    Join Date
    May 2008
    Location
    Allentown, PA
    Posts
    9
    My Cars
    2004 Bmw 325i

    anybody?

    Anybody have any insight on this issue? Please

  4. #4
    nathancarter is offline Stretch Haters Club #1 BMW CCA Member
    Join Date
    Feb 2007
    Location
    Tampa, FL
    Posts
    11,328
    My Cars
    2002 330i 131k
    I unfortunately don't have any good ideas on this one.

    I would speculate that if the problem were your FSR, it wouldn't matter if you were using the heat or the A/C.

    The only thing that should change (electrically, at least) when you turn on the heat is the baffles in the ductwork (I assume they're electrically/electronically controlled) and the heater valve (also probably electronically controlled). But, even if those were malfunctioning, they shouldn't have enough draw to make your battery light come on.

    I think I would pick up a voltmeter that plugs into the cigarette lighter (they're pretty cheap) and watch what happens when you do different things - rev the engine, change the fan speed manually, change the fan speed automatically, switch the A/C compressor on and off, etc. See if the voltage reported by the voltmeter has any correlation to the battery indicator on the cluster.

  5. #5
    Join Date
    Sep 2013
    Location
    Manchester, England
    Posts
    1
    My Cars
    X3, IS250, Rallye Golf
    Sorry to bring back an old thread, but did you ever get to the bottom of the problem? Having the exact same issue with my 2004 X3 3.0!

  6. #6
    Join Date
    Apr 2014
    Location
    CA, USA
    Posts
    1
    My Cars
    2004 325
    Ditto on bringing back an old thread, my 2004 325 is doing exactly the same!

  7. #7
    Join Date
    Feb 2018
    Location
    Piscataway, NJ, USA
    Posts
    1
    My Cars
    2006 BMW X3
    Quote Originally Posted by dydigital View Post
    OK i got a weird issue. Whenever i drive and turn the heat on my battery light comes on. when i turn the heat off then the light goes off after a minute. I can run the AC and no light. I originally thought it could be the alternator but i tested it and was getting 14v.

    Did some research and i see this article about the final stage unit/blower motor resistor? Only thing is i dont think i get speratic fan speeds, i only get the battery light. Do you think the resistor is the issue?

    I did get a Optima yellow top battery a while ago but that pretty much all i changed on the car

    Help please
    Please check the indicator on dashboard closely. i had the same issue. it is "low coolant" sign not a battery sign. Just check and top up the coolant, you will be good to go.
    I hope this helps.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •