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New battery, now I need to reset my navigation head unit each time I start the car...

Discussion in 'Car Audio Head Units' started by trax, Jun 10, 2011.

  1. trax

    trax New Member

    Hi guys,

    I'm cross-posting this at several boards to try and cast a really wide net and solve this problem. I haven't had much luck with google searches.

    Last summer I installed a Kenwood DNX5140 navigation unit and a Kenwood amp into my 1991 Toyota MR2. Worked great, no issues.

    This spring I noticed that my car battery was toast. I'd charge it overnight, and it would be dead after one day not being on the charger. It was an undersized battery (no joke--about 3 inches narrower than a stock battery). So I went to AutoZone and picked up the correct battery.

    I immediately noticed two things:

    • This new battery has WAAAY better cranking power than the old battery. No more issues with letting the car sit for days on end.
    • Each time I start my car, the head unit "freaks out" and won't power up. I need to press the reset button several times in order to get it to power on.


    Here's a detailed breakdown of the symptoms:

    • If I start the car, I need to reset the unit.
    • I then turn the car off.
    • Now that the head unit has been reset, and I've shut the car off, if I turn the key to ACC or ON (but don't start the engine) then the head unit can still power up.
    • If I start the car (with the head unit on) the head unit stays on for 1 second after starting, then shuts off, and I need to reset it.
    • If I start the car (with the head unit off) I need to reset it in order to turn it on.

    The head unit is wired up using a Metra harness and crimp connectors. I have tried shaking the harness around while the head unit is on, and I don't notice any strange behavior. The head unit gets its ground directly from the harness.

    Has anyone ever seen this problem? Any idea what could cause it?

    This is a new issue to me--I never saw this happen at all last year.

    Thanks
    --Peter
     
    trax, Jun 10, 2011
    #1
  2. Promodmerc

    Promodmerc Full Member

    I would check the battery connections, battery cables, positive cable connection at the starter, ground connection cable at the frame. When you start the car it is drawing way too much current and that is why the radio is freaking out.
     
    Promodmerc, Jun 10, 2011
    #2
  3. Fbmowner

    Fbmowner Full Member

    This seems really strange.. From what ive read it seems the unit works fine if you turn on your acc/ignition while the engine is off. Once the car is running it all seems to fail, correct? Off the top of my head all i can think of is the voltage from your alternator maybe? Check your voltage at the unit with the car off, then on. It shouldnt be over ~14-15. Another posibility is that the battery was hooked up backwards when it was installed and maybe fried something up inside the unit but that doesnt seem liable since it works when the engine is off. Id start with the checking the voltage when the car is off and on.
     
    Fbmowner, Jun 10, 2011
    #3
  4. deadz67

    deadz67 Full Member

    i`m not a mechanic, so don`t read this as the solution. But it sounds like your voltage regulator is gone, so it is sending too much juice causing your deck to go into protect & shut down. Once the car is started & amps have settle with everything drawing, the deck restarts & resets since it was in protect.
    i wouldn`t be surprised this is what killed your first battery as it was constantly being unloaded with each start.
    I`d say check your regulator
     
    deadz67, Jun 17, 2011
    #4