Bring modern performance to your classic GM truck with this 1977-87 Square Body Chevy & GMC Truck Heavy Duty Power Window Harness. Designed to deliver faster, more reliable window operation, this harness upgrades the factory system by drawing power directly from the battery, instead of through the window switch like the original setup. The result is stronger power delivery and modern window speed your Square Body deserves.
This heavy-duty harness features separate relays for up and down functions on both front doors, reducing strain on factory switches and ensuring smooth, consistent performance. Engineered as a smart upgrade for restorations or daily drivers, it integrates seamlessly with your truck’s wiring and works with factory power window switches.
Each kit comes complete with everything needed for installation, along with detailed instructions to guide you through the process. With durable construction and proven reliability, this harness is the perfect solution to maximize the performance of your Square Body’s power windows.
Key Features
- Fits 1977–1987 Chevy & GMC Square Body trucks, Blazers, Jimmys, and Suburbans
- Heavy-duty design for improved power delivery and reliability
- Draws power directly from the battery instead of switch circuit
- Separate relays for up and down functions on both front doors
- Compatible with factory power window switches
- Complete kit with everything needed for splicing and installation
- Includes step-by-step installation instructions
- Ideal for restorations, upgrades, or daily driver improvements
Give your classic Square Body Chevy or GMC the power and reliability of a modern system with this heavy-duty power window harness upgrade.
Don't forget to replace your 82-87 Classic C10 power window regulator driver side, 82-87 Classic C10 power window regulator passenger side, 1977-1981 Classic C10 power window regulator driver side, and 1977-1981 Classic C10 power window regulator passenger side.
