Where you run the green wire depends on when you want to be able to use the lamps.
This is what Hella was trying to get at with the examples in the pictures.
so if you want to be able to have the lamps on with the high or low beams or parking lamps, you would splice the green wire to the parking lamp wire ( Ford this is the brown wire )
Same for low only or high only, splice the green wire to the correct wire for that function.
Q1 -> did that make sense ?
You can get into some different options by splicing to a given wire on the back of the main headlamp switch, so you have have the lamps operational with the low or high, but not when the parking lamps are on. Don't know if you want to get to that level of detail.
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The switch diagram I have from a 500/550 kit, shows the order of the wires ( with the switch installed so up is on like a house switch )
Top = Ground
Middle = Yellow wire to the relay
Bottom = Green wire to lamp selection from above ( parking lamps, low beam, high beam )
You might have a different switch or were holding it upside down with the order you had. Not too sure which it is.
As for adding another lamp to the existing harness, the version I have shows a 15A fuse in the harness, which depending on the lamp wattage, the 3rd lamp would be right at the limit or just beyond it. Either way, add the 3rd lamp, and a harness for it.
You can use the same switch to operate the relay for the additional harness, by splicing the wire to terminal #86 ( on the 2nd relay ) to the yellow wire on the back of the switch ( basically jumpering pin #86 on relay #1 to relay #2 and the remainder of the install to the battery and the lamp are the same )
Linear Mode
