Here is a helpful link: www.allelectronics.com;
a company that deals with surplus components such as LEDs. Please note this is one of many companies in this business, All Electronics was the first that came to mind.
Catalog # CAT# LED-12W is a Bright 5mm round white LED with built-in resistors for 12Vdc, 12mA operation. No external resistor required. Works well on 4-12Vdc. Dimmer at lower voltages. 35 Degree viewing angle. Lenses are tinted the same color as the LED when lit.
Note this requires DC and NOT AC to operate. Check your lamp power supply and add a diode in series if you have an AC lamp supply. A diode such as 1N4001 (50 Volts Peak Repetitive Reverse Voltage, 30 Volts RMS Reverse Voltage, 1 amp current limit) will do.
Looking at the specification sheet (http://www.allelectronics.com/mas_assets//spec/LED-12W.pdf
), you can see the unit is typically drawing 30 mA in continuous duty. Dropping the current decreases brightness.
Assuming 30 mA at 12 VDC, the series resistor is R=E/I or
R=12/.030, or 400 ohms (shown as R801 on the spec sheet).
So, once you have picked your desired LED, read the spec sheet for typical forward current, and have measured the lamp supply voltage, you can calculate the required series resistor. Since THIS LED already has a 400 ohm resistor, all you need to do is connect it up to the lamp supply (assuming DC voltage) and if the LED is too bright, add an external resistor to suit.
Put insulating sleeving on the exposed leads, wire it up, take a few photos and post your write-up and bill of materials. No kit required, and this is a fun, yet functional modification. If you discover the LED is making noise when lit, you can place a .001 uF disc capacitor across the LED terminals (had a bunch of LEDs that were noisy enough to serve as a noise bridge source, but that's another story).
Installing this assembly into an incandescent lamp base and you're ready to go. If this is too much effort, visit www.superbrightleds.com
or another vendor that provides LED replacements for incandescent bulbs ... cost for a 12 volt cool white lamp is ~ $5.00 each.
Please note this was quickly dashed off. If you find an issue or error, please feel free to modify as needed and pass along.
Identifying everyone not having the expertise of an extra-class with over 7 years as an extra is a poor example. Lead and teach.