The installation process logically begins with your Tahoe’s existing headlighting system, as it is the primary power source and reference point for your new circuit. You will not be tapping directly into the headlight wires, but rather using the headlight circuit as a reliable trigger for a relay. This is a crucial distinction. The high-current draw required by fog lights would overwhelm the headlight switch wiring, leading to potential damage. Instead, you will locate the low-beam headlight wire in the engine bay fuse box or near the headlight assembly itself. Using a “add-a-circuit” fuse tap or a quality posi-tap connector, you will connect the trigger wire from your new fog light relay to this low-beam wire. This ensures the fog lights can only operate when your low-beam headlights are on—a common legal and safety requirement—and utilizes the headlight system’s robust design to control a separate, high-amperage circuit safely.
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