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Thread: 2015 chevy LT2 headlights solution

  1. #1

    Post 2015 chevy LT2 headlights solution

    Hi

    Rather than reply to a thread I started earlier this year about the poor performance of the non LTZ 2014-2020 Impala, I chose to simply start a new thread regarding my solution.

    I researched the possibility of retrofitting this LT with LTZ housings which are native HID housings.

    However there are several issues of which the first is cost. These housings taken in pair is easily over a $1000 and that is before an aftermarket HID kit that fits the stock housing is even considered.

    Using existing circuitry may not be possible as it is likely the circuit triggering is probably done by the pcm, and the necessary bin code is not available or even exists to bring the LT pcm to mimic the LTZ models,

    Another problem is how to disable DRL function from the headlights and move it to bumper LED lights that function as DRL.

    The tech exists to do this but by the time you do the retro, it can easily run another $500-$700 just to disable and move DRL to another light source which is DOT approved.

    I never considered adding a LED or HID kit to the car's standard halogen projectors so I was left with one last option.

    Since these housings are 9005 bulbs, I elected to go with 9011 Toshiba HIR 1 bulbs and bought 4 of them from flea bay. These bulbs in properly aimed housings were a major improvement however since they were still used as DRL, lived only 2 months both expiring within 4 days from each other.

    I have now installed a kit to disable DRL function from the headlights and switch to newly installed LTZ bumper LED lights which have taken over the DRL function. Hopefully these will lengthen the Toshiba 9011 HIRs.

    I found and purchased OSRAM 9011 HIRs with what appears to be the iridescent coating the orig Toshibas had/have.

    I will replace both of these housings soon and that should make further improvement.

    I hope my solution with the non LTZ/Premier Chevy Impalas will help others trying to improve their night driving experience.

  2. #2
    Moderator Alaric Darconville's Avatar
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    Default Re: 2015 chevy LT2 headlights solution

    Quote Originally Posted by leigh1962 View Post
    I researched the possibility of retrofitting this LT with LTZ housings which are native HID housings.

    However there are several issues of which the first is cost. These housings taken in pair is easily over a $1000
    OUCH!

    Using existing circuitry may not be possible as it is likely the circuit triggering is probably done by the pcm, and the necessary bin code is not available or even exists to bring the LT pcm to mimic the LTZ models
    Maybe the body computer can be upgraded as well, but that is another wheelbarrow of cash.

    Another problem is how to disable DRL function from the headlights and move it to bumper LED lights that function as DRL.
    There is the DRL-1, and there may be body computer programming, either of which could be used to move the function to the front turn signals. There's no need to install additional lights on the bumper.

    The tech exists to do this but by the time you do the retro, it can easily run another $500-$700 just to disable and move DRL to another light source which is DOT approved.
    In North America, there's no such thing as DOT approval (we don't use a type-approval system like UNECE signatories), and your front turn signals should satisfy the DRL requirements. Also, disabling DRLs entirely is allowed in the USA (just be sure to turn on your low beams if you visit Canada).

    Since these housings are 9005 bulbs, I elected to go with 9011 Toshiba HIR 1 bulbs and bought 4 of them from flea bay.
    Be careful of counterfeits on eBay!

    These bulbs in properly aimed housings were a major improvement however since they were still used as DRL, lived only 2 months both expiring within 4 days from each other.
    The DRL voltage must be so low the halogen cycle isn't completing. If the DRL is on the low beam, it's 60%; on the high beam it's 50%.

    I have now installed a kit to disable DRL function from the headlights and switch to newly installed LTZ bumper LED lights which have taken over the DRL function. Hopefully these will lengthen the Toshiba 9011 HIRs.
    Are those bumper LED lights marked "DRL" in (not less than) 3mm high letters? Unless optically combined with a headlamp, DRLs require that lens marking. If they don't have it, they aren't DRLs.

    I will replace both of these housings soon and that should make further improvement.

    I hope my solution with the non LTZ/Premier Chevy Impalas will help others trying to improve their night driving experience.
    Super expensive, but it could be worth it. Not sure how many people will follow suit, but sometimes vehicle fandom causes people to spend LOTS of money on something.

  3. #3

    Default Re: 2015 chevy LT2 headlights solution

    Hi

    I felt that PCM and BCM flashing wouldn't be a option due to necessary cooperation with a dealership that would be far happier just selling a new car that helping to improve an existing model.

    This modification essentially uses LTZ hardware and LED lights to clone the function and appearance of the LTZ while at the same time hopefully, saving the HIR bulbs from early failure due to their being used as a DRL.

    Time will tell regarding the life extension of the lamps.

  4. #4

    Default Re: 2015 chevy LT2 headlights solution

    Quote Originally Posted by leigh1962 View Post
    I felt that PCM and BCM flashing wouldn't be a option due to necessary cooperation with a dealership that would be far happier just selling a new car that helping to improve an existing model.
    Did you ask, though? Or just assume? Dealer service departments aren't necessarily the friendliest places on earth, but they don't stay in business by turning away business. Flashing control modules is a high-profit operation (fast and easy for them).

    This modification essentially uses LTZ hardware and LED lights to clone the function and appearance of the LTZ while at the same time hopefully, saving the HIR bulbs from early failure due to their being used as a DRL.
    1. What LED lights, specifically, are you using?
    2. Something doesn't ring up to the right total about your early failure. DRL mode doesn't cause early burnout like this; I think you got faulty bulbs.

  5. #5

    Default Re: 2015 chevy LT2 headlights solution

    Quote Originally Posted by -Virgil- View Post
    Did you ask, though? Or just assume? Dealer service departments aren't necessarily the friendliest places on earth, but they don't stay in business by turning away business. Flashing control modules is a high-profit operation (fast and easy for them).
    I didn't ask in this case but I really doubt they would flash to a pcm and/or bcm that wasn't intended for this car's vin.
    Besides, the headlight housings with HID ballasts would be over a grand just in themselves. So cost prohibitive plus if this was successful, something would need to be done about disabling headlight DRL and using parking lights for DRL isn't an option,

    1. What LED lights, specifically, are you using?
    2. Something doesn't ring up to the right total about your early failure. DRL mode doesn't cause early burnout like this; I think you got faulty bulbs.
    They came from flea bay so not sure about the bulbs . As for the LED DRL, they are the same for the LTZ Impala.

    I am eagerly anticipating the OSRAM HIR1 bulbs with the supposed iridescent coating like the old Toshibas.
    Last edited by -Virgil-; 05-18-2021 at 08:22 PM.

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