Help with LED/Resistors

Discussion in 'General Electronics Chat' started by benzo, Feb 5, 2011.

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  1. benzo

    Thread Starter New Member

    Feb 5, 2011
    Hi all, I am new to this forum and would like your help

    I am trying to replace some 194 (t10) halogen 5w bulbs in my car with LED
    this is what i have purchased:

    the problem is that this bulb consumes about 1.5watts, and my cars monitoring system is detecting a "burnt bulb", because its not 5w.

    i would like to know what resistor i need to add to the bulb to add 3.5w.
    also will i need to heatshrink the resistor due to heat?
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    A 39Ω 5Watt (the minimum rating) resistor connected in parallel with the LED unit - probably a wire wound type. Did you really mean "heatshrink" rather than heatsink? You wouldn't heatshrink the resistor as that would reduce its effective rating. Perhaps it would be prudent to mount the resistor in such a way that it doesn't overheat anything located nearby. You could consider using a 10W resistor rating to be more conservative - as long as you have the space to fit it in.

    The 39Ω would add an additional 3.7W at 12V DC.
    benzo likes this.
  3. SgtWookie


    Jul 17, 2007
    I'd have to consider this a modification of safety automotive lighting systems, which places the thread beyond the scope of the forums.

    You should replace the bulbs with the same part number that is listed in the drivers' handbook that came with the vehicle.

    Please abandon your idea of using a resistor in parallel, as that will defeat the "burnt bulb" warning system, along with requiring a modification to your autos' wiring harness; neither of which is desirable. Simply using the proper halogen bulb in the socket that was provided for it should give years of reliable and safe service.
  4. bertus


    Apr 5, 2008

    Please use the equipment supplied by an autorized dealer for your car.

    Automotive Guidelines

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