Hi I purchased this kit from Amazon. It had led's and resistors. If I had to guess, the ABS sensor has a built in 100 ohms resistance when you add a 100 Ohm resistor to the circuit it lights up the LED. I also purchased a Spare ABS sensor off of EBay so I could test this thing. And not break my OEM sensor, just in case. But it did work for me, my rear brake sensor was bad. You need to jack one end of the bike up so you can spin tire. Also both of my wheels had 2 shims under the ABS sensor . Good Luck.

BOJACK 630 Pcs 17 Values Resistor Kit 0 Ohm-1M Ohm with 1% 1/4W Metal Film Resistors Assortment Kit: Amazon.com: Industrial & Scientific
BOJACK 630 Pcs 17 Values Resistor Kit 0 Ohm-1M Ohm with 1% 1/4W Metal Film Resistors Assortment Kit: Amazon.com: Industrial & Scientific
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