Review on 🔌 5-Pack Waterproof Relay Harness - 40/30 AMP 12V DC, Heavy-Duty 12 AWG Tinned Copper Wires, 5-PIN SPDT Bosch Style Automotive Relay by John Kachinosky

I read DN's wiring instructions and my fog/LED lights were not working properly. So I turned off the power and built a test circuit with an additional relay. This is how the wiring works. Red wire - power IN. Black wire - GROUND. White wire to SWITCH to turn on relay. The blue wire supplies POWER to your device. The yellow wire PASSES POWER THROUGH the relay when it is off. Here is an example. With 2 fog lights (Right and Left) connect the OBE wire to the blue wire and when the switch is off, the relay will not work and the headlights will not light. Suppose you want to switch between two devices. In my case for my old truck, front and rear fuel tanks. I can connect the front to the blue wire and the back to the yellow. When the switch is off, the yellow wire (rear tank) is powered. When the switch is turned on, power switches to the blue wire (front tank). Hope that helps.