This mini-site was made to help owners of 6th Generation Accords to change their Dash Backlighting to LEDs.

Ok now it's time to get our LED's straightened out. I'll show you a few tips along the way

This is a stock bulb with it's crappy green rubber sleeve on, the light is even, but the color is just foul.

Here's one of the 3mm LED's that I'm using hooked up to the same power supply, this one is already in the socket

Here's one of the 5mm LED's on the same power supply. It's little bit brighter, and a slighty different pattern. I couldn't set the exposure on my camera so the actually luminosity may differ.

If you notice on both of the previous pictures the beam pattern is very tight compared to the stock bulb. This is a problem. There are very expensive LEDs out there that will give you a very nice wide beam, but I'm a cheap bastid. So on to my fun.I needed a way to get around the tight beam without spending a lot of money. The normal lens on the LED seemed to be the problem

I started playing around with the lens. I found that if I flattened the lens and left the flat part a little rough, I got a nice clean dispersed pattern. I used a cordless dremel with a cutoff bit, but be creative, a bench grinder, or even some sand paper will do.

Here's the beam pattern of the 3mm LED after I flattened it. Notice how smooth and wide the pattern is. This is what you want or you'll have hot spots on your climate control.

Here's a few LEDs after I've done my little modification

Well, now that we have the beam pattern right we need to figure out how to power our LEDs. I won't go into any DC theory as I don't want your head to explode, but LED's or Light Emitting Diodes have a specific current draw they like to see at a given voltage. Most diodes will have their specifications written on the side of the packaging or you'll be able to find a datasheet somewhere for them. My particular LEDs wanted 4.5 volts, and ~ 80ma of current. Here's the problem, normal cars use a 12v electrical system, that can peak as high as 15.3 volts. If you plug a diode straight to your battery the diode will die, and might even blow up(little pop, not a big BOOM, but enough to throw something into your eye). At higher voltages diodes will try to kill themselves by pulling too much current.To limit the current we need to introduce a resistor. A resistor adds "resistance" to the line and makes it so the diode only get's a certain amount of current. It also drops a voltage across itself so that the diode won't see the fill 12-15volts on it's pins. If you're curious about resistors look up ohms law on the web. Now orginally I had planned on using regular paper core resistors and found that they were just too big and I didn't like how they looked, and in some cases the damn bulbs just would not fit afterwards. I was over at the design lab at my work when it hit me. Why not use surface mount resistors, they're small, and they work great. So I snatched up a few different values and ran back over to my cube to play. Here's a picture of the difference between a regular resistor(top), and a surface mount(bottom), regular resistors are coded by their color bands, SMD resistors are coded numberically, 331 is 330 ohm, a 332 would be 3300 ohm, and a 330 would be 33 ohms. It's the first two numbers times the 10 to the power of the last number.

I know, I've probably give you a headache by now, but some things needed to be said. Ok now we know we need to use resistors to limit the current but what size resistor? I hate to say it, but I don't teach electronics theory so I won't go into it. For the LED's I have, the optimal resistor was a 680ohm resistor. But the LED's weren't pulling their peak current, which made them a tad dim, so I just started playing with resistors, will I found one that I liked. I tried the 330 ohm resistor and it looked great, but I left one on for 24 hours on the bench and eventually the LED died, so it meant I had just a hair too much current going through it, so I backed off to a 470ohm resistor. One key is to feel the resistor and diode after a few minutes of use, if they are HOT there's too much juice, use a higher value resistor. I found that 470 for my LED's was perfect and they've lasted for 3 months and counting with no problems.

If you use different LEDs that I did you may need different resistors, so be careful, just start out with a modest value like 680 and step down 100ohms at a time till it's too much. The LED's I got were from www.allelectronics.com and the product #'s were as follows.

T1 BLUE LED
CAT# LED-59
$3.75

ULTRABRIGHT BLUE LED, T 1 3/4
CAT# LED-74
$2.85

Now we need to take all of our bulbs and convert them. Take the stock bulb out, you might need a used staple or something to pick the leads up from the stock bulb. Now insert the LED through the same holes, and note which side is the anode and which side is the cathode. Unlike regular bulbs LEDs are polar and will not work if you plug them in the wrong way, they care which way you plug them back in. The anode is the + lead and is longer than the other. So I could remember I bent the cathode into a groove on the bulbs, inline with the leads of the LED then I bent the anode 90° to that. Now you need to solder on the resistor. I had some trouble with the leads of the LEDs being too thick if I tried to use them as the contacts, so I cut the leads at the edge of the bulb, and used 28gauge wire to hook everything up. Here's an illustration of what I did.

On the last illustration I say 330ohm resistor, I found that to be a problem and have 470ohm resistors instead, as shown in this picture.

In this picture I note which side is + so you know where the anode of the LED should go. And that's pretty much it, put your LED's in, put everything back together, and pray it worked :)