GMC R3500 Wiring Harnesses & Electrical - OEM-Fit Harnesses & Components

Restore your GMC R3500’s electrical system with precision-engineered wiring harnesses and electrical components designed specifically for your vehicle. Each harness is manufactured to match the original routing, connectors, and circuits of your GMC R3500—restoring the wiring behind the dash, under the hood, and through the body to factory-correct, or factory-improved, condition.

Our GMC R3500 electrical lineup includes complete wiring harness sets, battery cables and ground straps, switches, electrical devices, and update/conversion products such as alternator upgrades and electronic ignition conversions. Every component is manufactured and tested to deliver dependable, factory-correct performance, and is organized by your vehicle’s exact year to ensure the harness or component you order is the one built for your GMC R3500—not a close approximation.

Use the Vehicle Selector above to find the correct wiring or electrical component for your GMC R3500, or browse below to explore available options. Whether you’re chasing judging points with a numbers-matching restoration or simply getting your GMC R3500 running right, Factory Interiors makes it easy to restore your electrical system with wiring products proudly made in the USA.