I have a question; my car is 2017 Hyundai Elantra.

The output of halogen lights is not good on the highway. I really can't see the road and my car is new and under the dealer warranty.

I decided to install a LED set (H11 low / H11 high) but am worried about any side effects that may caused to the electrical system.

The question is / What is the possibility of the LED having a negative effect on the car electrical system or interference to the car equipment?

  • 1
    Fitting LEDs to a model car should not be an issue.
    – Solar Mike
    Commented Sep 29, 2018 at 21:16
  • What exact LED set did you get? Commented Sep 29, 2018 at 21:44

2 Answers 2


Replacing halogen bulbs with LEDs will not have a negative effect on the electrical system.

Some cars have a lamp testing system that will alert you if the bulb isn't drawing the correct power (burned out) and LEDs, due to their lower current draw sometimes cause these to alert. However this isn't an issue with your car. As a matter of fact, the bulbs will draw less power and last longer, with better light output, so it's a win.

  • Some countries require cars with led lights to have adjustable beam aim as part of the”fitness test” and it will no longer meet the standards for use on the roads.
    – Solar Mike
    Commented Sep 30, 2018 at 6:31
  • @SolarMike Ah, yes, as in dipping headlamps. That mechanism would be a mechanical system operating an eyelid (as in my car but it has HIDs) or moving the reflector for halogen bulbs. It should work in the same fashion for the LED bulbs, as most of the elements are shining out the side to the reflector, with only a few of the individual LEDs pointing forward. School me if I need it.
    – David Sain
    Commented Sep 30, 2018 at 7:01
  • 1
    Some cars have automatic adjustable aim systems for leds that are NOT fitted on the halogen bulb equipped models. I have a car model that has exactly this distinction - automatic adjustable aim for leds and a manual adjustment for halogen. This is not a dipping system that changes from main or full to dip when an oncoming vehicle appears - that is different.
    – Solar Mike
    Commented Sep 30, 2018 at 7:08
  • thank you all of you this very useful information and mr salin I need clarify for this line (if the bulb isn't drawing the correct power (burned out) and LEDs) did you mean the car system if not recognize the led will cause burn ?!?! Commented Sep 30, 2018 at 10:32
  • @SamIhakim, you don't need to worry, the LED draws less power than halogen and won't cause anything to burn.
    – David Sain
    Commented Oct 1, 2018 at 0:33

As has been pointed out the fitting of leds is not an issue; they fit and electricity use is lower.

What is a problem in some countries is that led lights are required to have an automatic headlight aim levelling system to aviod dazzling oncoming drivers.

If the car has leds retro fitted, then the car may fail a subsequent “fitness test” (MOT, roadworthy test, inspection ) as it no longer meets the standards set for that car / country.

It may also be the case that, while it may not have been tested since having the leds fitted, if it is in an accident and the insurance inspectors note the alterations then it may no longer be insured...

Edit: automatic adjustable aim is not the same as a headlight dipping system changing from full or main to dip for an oncoming car.

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