Head Unit Power (Fiat Ducatto) ICE question

Discussion in 'Tech/Mech General' started by Biggles, Jan 28, 2014.

  1. Biggles

    Biggles Funster

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    I have just fitted a new double din head unit to my Autotrail Cherokee. The Ducattos doesn't have an ACC stop on the ignition switch.

    As I understand it and I'm happy to be corrected, the yellow wire is a constantly fed wire to keep the memory of the head unit and draws very very low current and the red wire is the power delivery to run the unit.

    The problem comes when I want the head unit on when the MH key is out. As there is no ACC stop on the ignition as soon as the engine is stopped the head power is cut.

    The obvious solution seems to be to join the red and yellow wires but I'm told this will keep the head unit in a standby state and quickly drain the battery.

    The only other way I can see of solving this is to put a switched live from a permanently live source to provide power when the key is out.

    Is there a better way?
     
  2. Jim et Lou

    Jim et Lou Read Only Funster

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    My unit is wired in so that I can have the radio on without the key in and I have not had a problem as yet with battery drain (touch wood). I think that you switch the wire to the live feed on the ignition to do this.
     
  3. DP_JAY

    DP_JAY Funster Life Member

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    I've just fitted a DAB unit & simply disconnected the red & connected it to the yellow.(don't bridge across them or the ignition will stay on).
    The unit can be switched off at the normal power on/off on the face or by removing the face.
     
    Last edited: Jan 28, 2014
  4. Techno

    Techno Funster Life Member

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    [​IMG]
     
  5. Xabia

    Xabia Funster

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    I have taken a switched live feed from the leisure batteries to the red wire, that way it has cut down on interference from the engine, improved reception, I can have the radio on when stationary and no danger of depleting the starter battery.

    Mike
     
  6. Techno

    Techno Funster Life Member

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    The red wire in my picture is from my leisure batteries and switched from the Rapido control panel. They have fitted diodes so the ignition feed can still be used also
     
  7. Biggles

    Biggles Funster

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    What is the green wire doing?
     
  8. Techno

    Techno Funster Life Member

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    I knew someone had to ask :Laughing: I'm affraid that is a question for Rapido.
    As it is working with the ignition on OR with AUX2 from the Rapido control panel I've had no reason to alter their work and it would need a fair bit of dismantling to follow what they have done.
    The converters harness contains a red and a green both apparently +ve and a pair for the rear speakers.


    EDIT at a guess I would say the red to the yellow is unswitched from the leisure battery instead of from the starter battery and the red to the diode is the ignition acc and the green to the other diode is from aux2 to acc
     
    Last edited: Jan 29, 2014
  9. Biggles

    Biggles Funster

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    The problem is solved. A new wire from the MH side now provides power to the head when the ignition is off. This means the head can never draw power and drain the start battery.
     
  10. Stewart J

    Stewart J Funster

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    My 2013 Mohawk seems wired similarly ie from leisure batteries operating the 12 volt isolator switch kills the head unit power also. Seem to recall previous van a 2010 Tracker was wired via a fuse directly from vehicle battery. Though I stand to be corrected.
     
  11. eddievanbitz

    eddievanbitz Trader - Funster

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    "Toggling" the +30 (Ignition) wire is important in Navigation head units. In essence when the "ignition" is turned off, it resets things and dumps cancelled routes and POI searches that remain in the memory. Also, it turns the gyroscope and electronic compass off to conserve power.

    So quiescent drain isn't the only issue.

    A secondary feed like in Techno's Rapido is the best solution, or a simple dash mounted ON/OFF switch in the ignition supply will solve the issue

    Eddie
     
  12. Biggles

    Biggles Funster

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    Finally got all the bits and was able to finish the fit of a double din head unit. I now have some decent sound, all the freeview through the head and the overhead, DVD in both screens, full bluetooth phone and music streaming, remote control, USB input and of course a BIG reverse view.

    [​IMG]

    [​IMG]

    [​IMG]
     
  13. peterc10

    peterc10 Funster

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    I think Rapido are one of the manufacturers who do provide an additional switched lead from the leisure battery so the radio can be used with the ignition off. That is not standard on Ducatos and other converters do not do it.

    From memory the red is the switched ignition feed and the yellow is the permanent live (from the battery). As I understand it it is the yellow (permanent live) that supplies the main power to work the unit. The red is merely a switching current; when it is live the unit it turns on and when it is dead the unit turns off.
     
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