TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

When to know if a switched 12V is On or Off?

Discussion in 'Model S' started by dsevigny, Aug 10, 2016.

  1. dsevigny

    dsevigny Member

    Joined:
    Oct 17, 2014
    Messages:
    15
    Location:
    Montreal
    First, sorry about my bad english, I'm French!

    Let me explain what happen with my 2014 S85 (RWD /w autopilot).

    Last month, I installed a blackvue dashcam with the "ALWAYS ON" 12V available in the mic area. Everything works as expected and the dashcam is really always ON even when the car is Off.

    Last week, a proffessional installer installed the NVX Sub/Amp. (At my request, the Amp was installed in the trunk instead of in the frunk like many people do)

    Now my problem......

    I just realized that the Amp is always ON (Blue light) even if the car is Off. Look bellow the picture of the blue light ON. I tried to put my keys at least 30' far from the car, etc.... The Amp is always ON !!!!!! The installer confirmed that he wired on a switched 12V.

    Maybe I'm wrong but I remember that my cell phone stopped charging on the USB when I let this one in the car and start charging when I'm entering in the car so I assumed that th USB is a swicthed 12V. So now my cell plugged on the USB is always in a charge mode even when the car is Off. I made this test see when exactly the car accessories turn Off. Weird...

    I'm really confused and try to understand and avoid the Amp to drain my 12V battery....maybe not enough but I want to avoid that if it's possible.

    Thanks
    Dominic

    [​IMG]
     
  2. Tech_Guy

    Tech_Guy Always in Ludicrous mode

    Joined:
    May 6, 2016
    Messages:
    466
    Location:
    Los Angeles
    to confirm a switched 12v should be switched off when the car is off, an always on 12v is just that always on...

    Also my cellphone stops charging as soon as I exit my car and shut the door the displays go dark and the usb port stops working. When the door is opened again the displays light up and the phone continues charging.
     
  3. msnow

    msnow Active Member

    Joined:
    Jul 14, 2015
    Messages:
    4,232
    Location:
    SoCal
    Pretty sure USB is always on.
     
  4. Tech_Guy

    Tech_Guy Always in Ludicrous mode

    Joined:
    May 6, 2016
    Messages:
    466
    Location:
    Los Angeles
    my phone makes a noise when charging starts and I can hear this noise when I open my car door / turning the car displays and USB ports on again
     
  5. msnow

    msnow Active Member

    Joined:
    Jul 14, 2015
    Messages:
    4,232
    Location:
    SoCal
    I must be wrong then because you're saying it goes to sleep.
     
  6. Tech_Guy

    Tech_Guy Always in Ludicrous mode

    Joined:
    May 6, 2016
    Messages:
    466
    Location:
    Los Angeles
    #6 Tech_Guy, Aug 10, 2016
    Last edited: Aug 10, 2016
    I'm quite sure, I've also seen a thread on here about jumping a relay in the fuse box to enable always on usb and 12v... think its in the dash cam thread...



    Found it ...
    Anyone with manual access - any constant 12V in the cabin?

    FlatSix911 posted this which was quote of 2 other members


    Thanks. Unfortunately I don't really want something always connected to the OBD port (I like my installs to be all wired-in without any unnecessary wires showing). As for searching FlatSix911, I did, nothing popped up (here or on google, go ahead, search "12V power at the convenience plug", or even "12V convenience plug" :)

    - all I found searching was OBD port and microphone grille). I know there is supposed to be a 12V source in the cabin somewhere, but I don't have access to the service manuals.

    Here you go ... :cool:



    BTW, it's a simple matter to keep the 12v outlet in the console live all the time if desired. It's just a simple relay in fuse box #2 (the one on the passenger side under the removable cowling cover - see owner’s manual). Simply make up a jumper consisting of short piece of 14AWG or better wire with a couple of male 1/4" spade terminals.

    Pull the front most passenger side relay out and insert the jumper into the now exposed 1/4" female receptacles, and you're done, the 12v outlet is now on all the time. You can quickly change it back anytime by removing the jumper and reinstalling the relay.

    [​IMG]
    [​IMG]
     
  7. dsevigny

    dsevigny Member

    Joined:
    Oct 17, 2014
    Messages:
    15
    Location:
    Montreal
    I make a test this evening! I plug my cell phone in the USB at 51%, closed everything and when I came back 30 min after, the cell was charged at 61% !!!!!!! Never happen before... I really need to understand what happen with my car! I'm pretty sure that the installer doesn't make the relay jumping in the fuse box just to plug the Amp.... I'm still confused....and stressed about that!
     
  8. Tech_Guy

    Tech_Guy Always in Ludicrous mode

    Joined:
    May 6, 2016
    Messages:
    466
    Location:
    Los Angeles
    #8 Tech_Guy, Aug 10, 2016
    Last edited: Aug 10, 2016
    id check your fusebox #2 located in the passenger footwell to see if its been jumped as shown above...
     
  9. msnow

    msnow Active Member

    Joined:
    Jul 14, 2015
    Messages:
    4,232
    Location:
    SoCal
  10. Tree95

    Tree95 Member

    Joined:
    Oct 24, 2014
    Messages:
    192
    Location:
    Usa
    The photos were originally posted by me Near annual replacement of 12V battery is typical according to Tesla Service Tech

    In my March 2015 S85D, left hand drive, the fuseboxes are in the frunk under the the removable panel that runs across the rear of the funk near the windshield.
     
    • Informative x 1

Share This Page