LED Instrument Illumination Options

[GeorgeRud]

Has anyone converted their instrument panel illumination lights to LEDs yet? They are being sold as upgrades and are supposed to make the instruments brighter (good for these older eyes). I know the 2 watt bulbs can be replaced with 4 watt bulbs, but I was warned by North Hollywood Speedometer not to do it as the extra heat generated will eventually fry the innards of your instrument. I like the idea of brighter instruments however.

[bondo]

QUOTE (bd1308 @ Aug 26 2005, 10:58 AM)

who said they weren't dimmable???? i've played with LEDs for years....there as dimmable as a regular bulb.

They are indeed dimmable.. but say your LED needs 3 volts for full brightness.. half brightness will not be 1.5 volts, but something more like 2.8. So once you add the resistor to the LED so it gets 3 volts from the 13.8v system, you need to be able to drop that voltage to something like 12.5 volts. Now your stock variable reststor for the instrument lights is probably 10 ohms or so.. When compared to the resistor needed to give the LED 3 volts at 13.8, that's nothing. All this gets thrown out the window if the LED modules have an internal regulator (which they might). If that's the case they will be the same brightness from 15v all the way down to something like 3.2v, because the regulator will vary its resistance to keep the voltage to the LED itself at 3v.