What is the extra yellow wire to be used for? 4 pin harness plugs into truck. Extra yellow wire is for what?

Thank you for your inquiry.There are altogether 5 input cables for the product and external. The Brown wire is power wire, hook up to negetive. The other 4 signal wires touch the positive wire to change colors or modes.Brown wire: Connect to negetive pole.Green wire : For turn right amber light. Yellow wire: For turn left amber light.White wire: For brake amber.Red wire:  White running light.

Are these strip lights dot approved

Hi, sorry , it is not dot approved