Introduction: 10mm LED Motorcycle Instrument Light Conversion

I thought it would be a cool idea to replace the old instrument lights on my bike with LEDs

Not only would they be vibration resistant, but they'd also emit less heat and drain very little power

Step 1: Components Needed

• 10mm diffused white LEDs - I found that these were almost exactly the same diameter as the old bulbs

• 1 Watt rated Resistors (~470ohm) - See step below on how to calculate resistance needed


• 2 pin male/ female connector blocks

• 12V Power supply/ battery for testing

• Go for LEDs matched to the coloured filters for better colour quality

Step 2: Stepping Down Voltage


• Find the specs for the diode you're going to use. The 10mm white LED I chose: 20mA @ 2.9 - 3.3V

• The regulated voltage on my bike is ~12V

  • Use Ohm's law, in this case for resistance, to calculate the approx. resistance value needed to drop 12V less the LEDs forward voltage, to a usable 3V*

R(Resistance) = V(Voltage) / I(Current)

9V / 0.02A = 450Ω

You'll need a resistor close to this value for the LED described above

• Next let's calculate the power consumed by the circuit

P(Power) = I(Amps) * V(Voltage)

0.02A * 3V = 0.06W

*There are better, more efficient ways to rectify voltage, but this is without a doubt, the easiest method

Step 3: Light Up

• I first made a mark to indicate the polarity. The shorter leg is usually the cathode (-) (Check this before going any further)

• Cut the LED anode (+) and resistor to length

• Clamp both components in a clamp or as I've done: with crocodile clips

• Solder LED (+) -> to the resistor

• Check if it works!

Step 4: Tidy Things and Install

• Put some heatshrink around at least one of the exposed LED leads to avoid short-circuits

• Add a 2 pin connector to the finished circuit and motorcyle headlight wiring harness, or as I did, just connect together directly

• Stick the LED into the clock case and fix in place with some hot glue or silicone

• If your bike lives outside, consider potting the LED and resistor in silicone sealant