Originally posted by SumAccordGuy94
resistors.
5 Volt LED's huh? whats the item #??
typically LED's work from roughly 1.7-1.9 volts.
huh????? most LED's have a forward voltage 3-5vDC . The resitors are used to clamp the current not the the voltage. The bias current is the thing that concerns you, some of the newer LED's can want as much as 100ma, underdriving them won't hurt them though, it will just make it so they aren't that bright.
Your theories are close, but not quite accurate, so here's a little extra mind numbing info. You using an arbitrary .020 without an explanation scared me. The proper formula is (source V - LED Forward V) / Forward Current. In the case of the LED's I used for my dash (LED #74 from allelectronics.com) the max Forward V is 4.5, they have a forward current of 20ma(I have some LEDs that pull 50). So (15volts(rough # for a car electrical system) - 4.5volts) / .020A = 525ohms. I only had 470ohm SMD (Surface Mount Device) Resistors in stock so I hooked a few up and I played with them on the bench and did a 100hour burn-in in a climate oven at 85°C to see how they hung and they did great so that's what I used.
Also it doesn't matter which side the resistor is on.
Here's a quick little how to page I put together to help otehr 6th gen accord owners make their car look pretty
http://www.igd4u.com/ledaccord/
