Adding Rock Lights for 1999 GMC Sierra 1500 Off-Road Illumination apsense.com

Run the main harness along the frame rail, following existing factory lines and securing with zip ties every 12 inches. Route the switch wire through a firewall grommet—typically located near the steering column—into the cabin. Mount your rock light switch in an unused dash blank or in a discreet location below the dashboard. Connect the harness power leads to the battery (positive to positive, negative to chassis ground). Plug each rock light into the harness using the provided waterproof connectors. Testing is crucial. Reconnect the battery and activate the switch. The rock lights should produce a broad, even glow around all four corners of the truck. Adjust individual pod angles as needed. Most owners choose a crisp white light (6000K to 6500K) for maximum utility, but colored options—amber (reduces bugs and glare in dusty conditions), blue, green, or red—are available for style.