, I did a little research and I thought this might be helpful - (I would need a handy-person to interpret lol, but hopefully you have one of those in your life). This is a response to a product question on Amazon: "Ok, so here is the off the spec sheet review. If you are doing a dash light conversion of an older vehicle, this is likely what you are looking for. LED's are dimmed in a completely different manner than standard light bulbs. LED's use very little power, and will operate at the same brightness over a wide range of voltages, which is why you cannot get your old school dimmer to work. The way to dim and LED is to use a PWM (Pulse Wave Modulation) type dimmer. There are tons of these types of dimmers available on Amazon for super cheap, but they do not use a 3 wire system. unless your car uses an isolated ground for the items you are tying to dim, you won't get those to work, because they do the PWM on the Negative side of their output circuits.
This unit outputs the PWM wizardry (it really just sends pulses of electricity to the circuit to provide the dimming) on just one positive output wire. In my case, I intercepted the dash light circuit at the factory dimmer connection points, and connected the Purple to the power side of the dash dimmer, and White to the dash lamp circuit, and the Black to ground. Super simple with a voltmeter, and a few minutes to crimp on the right connectors, and plug it in on my Datsun Roadster. it would be a bit more involved on a domestic car with the dash dimmer in the headlight switch, but you shouldn't need to carve up the harness to get it done either."
I hope that may prove helpful! - Warmly, Donna (Health-Union Team Member)