LED Dash Bulbs?


chewy012

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Are the LED's dimable? I know with home lighting, LED's - some are dimable and some are not.
They do dim, but they also cut out and flicker.....

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Flash Gordan

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They do dim, but they also cut out and flicker.....

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I have LED's in the dash cluster of my 01 Sport Trac and haven't had any cut out or flicker.
 

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From my thread. I used cheap Chinese LEDs off eBay and they worked great

Got some blue 194's for the gauges



Installed, kind of a fuzzy picture, but I think it looks awesome



:icon_thumby:
 

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Mine's a '92, so it may just be a thing for older models

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Dash LED replaacement Bulbs

I have a similar question relating to low light after switching to LEDs.
FYI the truck is a 2009 Super Cab w/4.0L, auto & 4X4. It had the small mini bulbs - smaller than 194's. I replaced all with LEDs and now the dimmer switch can only iluminate the main gauges in very low brightness. That is with the dimmer set on high.

Is this a common issue with LEDs? The three LEDs in the turn signals and bright headlights work great but they are a different circuit from trhose on the dimmer switch.
 

ericbphoto

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I replaced all with LEDs and now the dimmer switch can only iluminate the main gauges in very low brightness. That is with the dimmer set on high.
Not all LEDs are equal. How many LED chips (SMDs) are on each LED assembly you installed? 1, 3, 5, more? This will affect the light output. There may also be different SMD chips with different light outputs.

I'm not an LED expert. But here is what I do know.

LED's are not resistive devices like light bulbs. If you have a resistor type dimmer for your dash lights, then it will not properly dim LEDs. LEDs are made to have a particular voltage across them ie; 2.1volts. In a circuit of higher voltage, a resistor is normally installed in series to drop the voltage and limit the current through the LED. In the LED assemblies we are buying to replace cluster lighting, the resistors are built into the assembly. When you turn your dimmer switch, you further reduce the voltage to the LED. It remains at almost a constant brightness until it stops conducting when the voltage across the actual SMD chip falls below the threshold.

The normal and best way to dim LED's is to use a pulse width modulated (PWM) power supply. This is a power supply that keeps the voltage constant, but turns the power on and off at a high frequency. The time that the power is on is a pulse. Varying the width of the pulse changes the percentage of time that the LED gets power - wider pulse, the LED is on more time per second than with a narrower pulse. The frequency is high enough that our eyes do not detect the flickering of the LED turning on and off. But the overall effect makes the LED appear to be dimmer or brighter. Newer vehicles may have LED lights and PWM power supplies for them. I can't tell you which ones do or don't.

Chances are, if your originally had incandescent lights, then you have a resistor type dimmer and LEDs will not dim properly.

I hope this helps.
 

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Not all LEDs are equal. How many LED chips (SMDs) are on each LED assembly you installed? 1, 3, 5, more? This will affect the light output. There may also be different SMD chips with different light outputs.

I'm not an LED expert. But here is what I do know.

LED's are not resistive devices like light bulbs. If you have a resistor type dimmer for your dash lights, then it will not properly dim LEDs. LEDs are made to have a particular voltage across them ie; 2.1volts. In a circuit of higher voltage, a resistor is normally installed in series to drop the voltage and limit the current through the LED. In the LED assemblies we are buying to replace cluster lighting, the resistors are built into the assembly. When you turn your dimmer switch, you further reduce the voltage to the LED. It remains at almost a constant brightness until it stops conducting when the voltage across the actual SMD chip falls below the threshold.

The normal and best way to dim LED's is to use a pulse width modulated (PWM) power supply. This is a power supply that keeps the voltage constant, but turns the power on and off at a high frequency. The time that the power is on is a pulse. Varying the width of the pulse changes the percentage of time that the LED gets power - wider pulse, the LED is on more time per second than with a narrower pulse. The frequency is high enough that our eyes do not detect the flickering of the LED turning on and off. But the overall effect makes the LED appear to be dimmer or brighter. Newer vehicles may have LED lights and PWM power supplies for them. I can't tell you which ones do or don't.

Chances are, if your originally had incandescent lights, then you have a resistor type dimmer and LEDs will not dim properly.

I hope this helps.

its easy to identify them at night. rapidly scan your eyes from side to side while behind one. the pulses will form a distinct row of several lights as they pulse on & off.
 

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Thank you Eric! Great explanation. Went with LEDs b/c the dealer wanted $32 each for the replacement bulbs. Will look some more for incandescents to replace the originals. Steve.
 

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Thank you Eric! Great explanation. Went with LEDs b/c the dealer wanted $32 each for the replacement bulbs. Will look some more for incandescents to replace the originals. Steve.
try searching any parts store site for 2721LL they are $4.99 for a pack of 2 at Autozone, brand is Sylvania.
 

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Thanks for the info. Picked them up yesterday.
 

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The other bulbs are T5 and T4.7


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