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Harness Help

Discussion in 'Gen 3 Prius Accessories and Modifications' started by GasSaver1, Dec 1, 2012.

  1. GasSaver1

    GasSaver1 Member

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    Hello everyone!
    I want to connect a harness like pictured here:
    http://priuschat.com/attachments/cimg1136-jpg.17486/
    With the power coming from the fuse box and the negative grounded to the car.

    My only question is- how can I safely do this? Do I need to disconnect the battery first or if I connect the ground first can I just loosen the power and slip it in without shocking myself or shorting the car?
     
    #1 GasSaver1, Dec 1, 2012
  2. jmrmotorhead

    jmrmotorhead Junior Member

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    What Is this harness for?
     
    #2 jmrmotorhead, Dec 1, 2012
  3. GasSaver1

    GasSaver1 Member

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    #3 GasSaver1, Dec 1, 2012
  4. xliderider

    xliderider Senior Member

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    If the harness has a fuse in it, which it should, then you can remove the fuse before making any connections.

    Make your connections to power and ground, then reinsert the fuse to complete the circuit. If you have made the right connections, there shouldn't be any power in the circuit anyway, because the circuit should be made live by a relay and not carrying power when the lights are not switched on.
     
    #4 xliderider, Dec 1, 2012
  5. GasSaver1

    GasSaver1 Member

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    Yes, it does have a fuse and that is great advice!
    My only question now is... ok the hot in the fuse box is live without me disconnecting the battery and I am wondering if I need to disconnect the battery or with everything as it is- if I just loosen the ground bolt (in the picture) and attach the harness ground, then loosen the hot in the picture (which will still be hot) and slip the hot lead from the harness under it and screw it back down if I could get a shock or fry something.

    My thinking is that if I connect the ground first, if there is a problem, voltage will funnel there while I am connecting the hot, though with the fuse disconnected, the circuit in the harness will be broken so voltage will never make it to the ground.

    I guess I am just trying to figure out the steps:
    1. remove fuse from harness
    2. connect negative from harness to the bolt in picture
    3. loosen positive in fuse box and connect to positive of harness

    or do I have to
    1. disconnect battery
    2. remove fuse from harness
    3. connect negative from harness to the bolt in picture
    4. loosen positive in fuse box and connect to positive of harness
     
    #5 GasSaver1, Dec 1, 2012
  6. Steve Robinson

    Steve Robinson Junior Member

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    Assuming that this is a feed from the battery (on one side of this post or the other, I have never looked), you should disconnect the battery. The risk here is that while wrenching the bolt your tool touches a ground point. Instant heat, and damage to things, possibly including you. You have confirmed with a meter that this is always 12volts?

    Some of us might try this without disconnecting the battery but you don't know how long that bolt is, if it will come off, if the items already attached will move around and if one of them is a live connection to the battery. Better to be safe than sorry.

    Speaking of which, I assume you are crimping a round flat (or spade) connector to your wire? Simply wrapping copper around the post and tightening it back down is not a great way to do this.

    Second over-opinionated comment: HID ballasts are designed to go on OEM wiring with peak loads LESS than the static load of the OEM standard 55w halogens. Most are 35 watts with a peak startup of about 50 watts (for a few milliseconds). The harness is really unnecessary and adds more failure points to the install and operation. Remember, watts has nothing to do with the brightness of the lights, only the current draw. 35watt HID are 2x brighter than 55w halogen, because the HIDs convert electricity to light 4x more efficiently.
     
    #6 Steve Robinson, Dec 1, 2012
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