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Replacing HU

Discussion in 'Gen 2 Prius Audio and Electronics' started by Erick, Nov 15, 2005.

  1. Erick

    Erick Member

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    I apologize for posting this. I know this has been discussed before and I've read many many posts on the subject but I am still unclear about what exactly needs to be done. I am replacing the entire system (speakers, HU, AMP) and I have the NAV and BT. I don't mind losing steering wheel controls for the HU since I never use them anyway. I don't, however, want to lose my nice map lady.

    I read DANMAN32's post saying that "You would want the new HU left front output fed to the NAV audio input, so it could control the left speaker sound source, switching between itself and audio. Mute is only done for BT or voice recognition."

    So basically, I would want to run the left output from the new HU into the NAV system that's under the front seat. I would plug this into the NAV Audio input. Then what? Does the NAV have an output that then goes into the AMP and then to the front left speaker? If this is the case, will this affect the sound quality of the left channel? I am trying to go with a unit that has 4 Volt pre-amps but if the quality will get lost going through the NAV, then I won't bother...

    Any help you can give me would be great. I want to give the installer as much info as possible before they start.

    THANKS!!! :D
     
    #1 Erick, Nov 15, 2005
  2. tmorrowus

    tmorrowus Member

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    The easiest way to go may be simply to use the factory wiring as much as possible, which already passes through the nav unit on the way to the front left woofer. So just have the installer run speaker wires down from the new head unit to the factory wiring which is accessible where it enters the JBL amp under the passenger seat. You can even buy the bazooka harness so you can tap in without cutting the factory wires.

    Then in the doors you wire your aftermarket speakers to the factory speaker wires.
     
    #2 tmorrowus, Nov 15, 2005
  3. Erick

    Erick Member

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    Thanks!

    When you say have the installer run speaker wire from the HU, do you mean the amp pre-out? I will be replacing the JBL amp so the preamp wires will go from the HU and into the new amp. Should I just take the existing speaker wires out of the JBL amp and plug them into the new amp?
     
    #3 Erick, Nov 15, 2005
  4. brettray

    brettray New Member

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    Basically, Yes. The NAV system expects an amplified signal. When it wants to use the speaker it simply disconnects the normal feed and sends out it's own amplified signal.

    I set up my system this way. Line level RCA's from the new deck to the new amp and then from the new amp to the speakers using the existing wiring. This made everything easier as all the wires already ran to the location of the new amp (under the passenger seat). I would have rather used new wiring (with a lower gauge wire) but I did not want to go through the hassle of feeding wire into the doors (the prius does not have any convenient holes to slip the wire through, just a solid plug with all the wires for the door).

    Also if you plan to remove the old head unit you will need to terminate the bus wires that run from the old head unit to the MFD. I used a 47Ohm resister and it worked fine.
     
    #4 brettray, Nov 15, 2005
  5. brettray

    brettray New Member

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    Almost forgot,

    I don't know how the mute signal from the NAV system can be interfaced with a new head unit, so Bluetooth and NAV will still work fine but the stereo will not auto mute when you receive a call.
     
    #5 brettray, Nov 15, 2005
  6. Erick

    Erick Member

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    Perfect - thanks everyone. This really helps a lot! :D
     
    #6 Erick, Nov 15, 2005
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