Possible Driver side Lowbeam Voltage Issue

Discussion in 'Gen 3 Prius Technical Discussion' started by sjsushiman, Sep 17, 2019.

  1. sjsushiman

    sjsushiman Junior Member

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    I am currently upgrading my stock halogen headlights to the Prius G's HID headlights, but after installing the assemblies, the driver side low beam will start up but quickly fade out while the passenger side light works fine. I have tried switching out the ballasts, wiring harnesses, and bulbs to see if one was defective but the problem persisted. Even after plugging in the passenger side assembly into the driver side the passenger side assembly that had just worked fine exhibited the same behavior of starting up but quickly fading out.
    Before replacing the assemblies I had noticed that the driver side was noticeably dimmer than the passenger side, but I figured it was because the seal on the driver side headlight was bad and water had somehow made it dimmer, but that seems wrong now. At this point the only conclusion I can come to is that it is an issue with the voltage being supplied to the driver side light. Has anyone experienced a similar problem? Are there any other possible issues/solutions I'm not thinking about?
     
  2. xliderider

    xliderider Senior Member

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    Install them using an HID wiring harness that draws power for the ballasts directly from the engine fuse box. The oem lowbeam harnesses are only used to trigger the relay(s) in the HID wiring harness.

    The relay(s) in the HID wiring harness can be triggered by a wide range of voltage, like 9v to 14v or even wider, so it really doesn't matter if you have a low voltage issue on one side.

    Posted via the PriusChat mobile app.

    I'm using a dual relay HID harness on both of my cars and have not had any problems.
     
  3. xliderider

    xliderider Senior Member

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  4. xliderider

    xliderider Senior Member

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    Get your power from the open 1/4 inch terminals at the rear of the engine fuse box. In my pic, it's either of the two terminals that have the red wires on them. They are 12v constant power, just like connecting to the 12v auxiliary battery positive terminal. 20130104_131155_zpsffc5d850.JPG

    Posted via the PriusChat mobile app.
     
  5. sjsushiman

    sjsushiman Junior Member

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    Thanks so much for the advice! I'll order the wiring harness you linked and let you know how it goes.
     
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