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HELP! Low beams out

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by guitarguy308, Oct 18, 2013.

  1. guitarguy308

    guitarguy308 Junior Member

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    ok heres some background info.

    My high beams went out a few months ago on my 2008 prius. They told me it was the relay. I just replaced it today with a relay from advanced auto parts. My highs work now. But as of 2 hours ago I noticed my lows are no longer coming on. A few days ago I picked up the car after having aftermarket hids put in. The lows were working then highs still no. A few weeks ago I had some other relays replaced and they told me the cap was off and water and shit got in it.

    So could it be that my low relays have gone bad now too? It seems weird right when I fix my highs my lows stop working. If its possible I want to try a new relay to see if that fixes it. But I need the part number and location in the relay box. I can post a picture of the inside of my relay box if someone can point to which one it is. Im sure it even has the part number on it. Let me know if I should or not.

    And thanks again for your help
     
    #1 guitarguy308, Oct 18, 2013
  2. Britprius

    Britprius Senior Member

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    It sounds as though you have a problem with the wiring of the aftermarket HID lighting. The low and high beam on most after market HID's is the same bulb "not a twin filament or light source bulb as the OEM fitting", it is only a moving shield that gives high and low beam.
    I have the Prius circuit diagram for the OEM if it will help.

    John (Britprius)
     
    #2 Britprius, Oct 19, 2013
  3. guitarguy308

    guitarguy308 Junior Member

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    Even though the lows were working before I changed the relay?
     
    #3 guitarguy308, Oct 19, 2013
  4. Britprius

    Britprius Senior Member

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    Yes, this suggests when you go to high beam the low beam is being switched off "the way the OEM circuit is arranged turning one filament off and another on". With the HID's the high and low 12v supplies have to be capable of feeding the single light source "via an inverter" to keep the single bulb alight. The high beam 12v supply also has to move the shield.

    John (Britprius)
     
    #4 Britprius, Oct 19, 2013
  5. Britprius

    Britprius Senior Member

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    It is most likely that at the rear of the passengers side headlamp you will find the original bulb supply connector. If you fit a known good OEM bulb to that connector and that bulb then works on low and high the fault lies with the new wiring. This wiring normally has an extra relay and also picks up a new fused 12v supply from the jump point.

    John (Britprius)
     
    #5 Britprius, Oct 19, 2013
  6. guitarguy308

    guitarguy308 Junior Member

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    Ok so what should I check for. The way the circuit is I believe and correct me if I'm wrong is that when I change from low to high it switches to a different circuit but on the hid because it's a single bulb all it does is move the shield and keeps a constant power supply.

    How could my lows have worked before and then not worked?
     
    #6 guitarguy308, Oct 19, 2013
  7. Britprius

    Britprius Senior Member

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    The best way to check is as I have already outlined in my previous post. If the bulb works on low and high the fault is in the new wiring. If the bulb does not light in either low or high or goes not change over the problem is with the OEM circuit.
    The most common place for a fault with the new wiring is with the ground connection to the new relay.

    John (Bitprius)
     
    #7 Britprius, Oct 20, 2013
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