I have no clue what polarity your LED manufacturer employed for their product.
Wouldn't it just be standard red-hot, black-ground polarity?
Standards are wonderful. That is why there are so many of them.
It's all about context. A manufacturer can chose pink and purple and assign any polarity requirements they chose, particularly if they got a good deal on odd color wires to improve their profit margin. It'll still work as electrons are color blind. But, it is their responsibility to relay what their color choice represents. Or, to ignore an unwitting buyer once a sale is made. Personally, I wouldn't buy an LED if I couldn't ascertain with certainty beforehand how it was to be connected.
Honda convention is Green for battery NEG and Black for battery POS (switched).
so I have it backwards, green is the traditional "ground" whereas the black is the "neutral?
Neutral applies to house/building AC wiring. Hondas are generally in the DC world for the most part (certainly the lighting). But, the labels/color codes are defined by Honda, not the National electric code.
In reality, Hondas have no actual "ground" as the tires insulate to any earth/ground connection. What is commonly referred to as ground, is a frame connection. It only behaves properly as a return in the current loop, if it is attached to the Battery NEG terminal. Any device on the Honda must ultimately connect to the two battery terminals in order for current to flow through the device. Closed switches complete a circuit, open switches defeat current flow in a circuit.
In my mind and my terminology deficient understanding, the one set of lights are activated when a contact is made, such as the blinkers. The other set is "activated" when the contact is broken such as a the oil or neutral lights. Now, I may have the examples backwards, but in principle...
Sorry, you need a revision in your "principle understanding", I'm afraid.
Current only flows in a circuit when the loop between battery and device is completed. LED's also require the polarity to be correct as well.
The oil and neutral light also illuminate when a contact is closed in their respective switches. In this case, the powered device has the circuit path completed to battery NEG terminal through a switch the connects it to "ground"/chassis/battery Neg terminal (all these three should be at the same potential in our Hondas).
No doubt you've connected a lamp to the battery. Didn't you have to use both posts? The frame or green wires in the harness are just an extension of that battery Neg terminal post.
A switch, whether it be in the power source path or the power return path, functions toward the same purpose, break (or allow) the current flow in the loop between battery and power using device.
LED's add the additional requirement that the applied polarity must be observed as well.
Cheers,
