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12V Posts behind Nose Cone

Discussion in 'Model S: Battery & Charging' started by pgiralt, Feb 17, 2014.

  1. pgiralt

    pgiralt Active Member

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    I need someone to confirm that I'm not going crazy. The red post and other post welded to the bumper under the nose cone should always measure 12V (well, really probably a bit higher), correct? I'm measuring no voltage across them with a multimeter and don't understand why. Is that connection fused somewhere? Could it be disconnected at the other end of the wire from the red post?
     
  2. tezco

    tezco Sig P85

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    Perhaps there is a blocking diode to prevent a reverse flow of current?
     
  3. Rainbow

    Rainbow Member

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    Did you connected the other multimeter lead to ground?

    Did you check the fuse in the multimeter?

    Did you test your multimeter on another battery?

    Was your multimeter on the right scale?

    Did you have the leads of your multimeter plugged into the right ports of the multimeter?

    If your multimeter has hold button/setting, was the hold set to off?

    Are you sure you got a good connection to the battery posts/or connectors? Often battery posts don't conduct well, because they are often covered with oxide or treated with a lacquer/paint. Sometimes you have to press hard or scratch with the probes to penetrate the oxidation or lacquer/paint.
     
  4. pgiralt

    pgiralt Active Member

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    Yes, the multimeter is working properly because I can measure other connections in the car and am seeing a 13.7V output, so it's not the meter. I found a picture of the battery here:

    Audio: Sound System Quality? - Page 8

    And it appears that there are a bunch of fuses bolted directly to the battery. I suspect my problem is probably one of those fuses is blown, but it looks like it's a lot of work to get to the battery to check.
     
  5. Rainbow

    Rainbow Member

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    If your vehicle is under warranty, it would probably be best to let a Tesla service center take care of it.

    Otherwise if you feel knowledgeable and are willing to take the risk.
    Suggest you go to the trouble to check the fuses. If problems continue suggest you get a wiring diagram.

    If there supposed to be power there, and there isn't. There is probably something bad, like a fuse, blocking diode, fusible link, circuit breaker, relay, connector, etc. Hard to even make a good guess without a wiring diagram.
     
  6. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    I have always measured it between 12.8 and 15V, it never has gone to zero for me.
     
  7. pgiralt

    pgiralt Active Member

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    FlasherZ, thanks for the confirmation. I'll have service check it out next time I'm in for something else.
     

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