hi guy and girl's what led brake light upgrade are u using as i got cree 80w led show bulb code but thay work in my drl's with no code and reverse / and fog all work fine ,,as back lights are tinted wanted to have better stop lights  thank's for your help .. oh car 2013 fabia monte carlo ..

Have you made sure that when you are pressing the brake pedal the bulbs actually illuminate and you have the polarity the correct way round? Does the bulb warning light come on as soon as you start the car ie when the car does its 'checks'

You may find that due to design of the bulbs and placement of the CREE chips that although the bulbs are brighter they do not work as well due to the lens housing not being designed for them.

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Wouldnt be using LED brake lights personally. The housing isnt designed for them and they probably wont be as visible as normal bulbs.

A tough one to explain in the event of an accident maybe...