Painless Wiring CirKit Boss Auxiliary Fuse Block Kit

The Painless Performance CirKit Boss is a professional-grade auxiliary fuse block system designed for enthusiasts and installers who need to safely add electrical accessories to any vehicle — without ever touching factory circuits. As the first circuit isolator system available with both constant and ignition-switched circuit kit options, the CirKit Boss line delivers the flexibility to power virtually any accessory while fully protecting your OEM wiring and factory fuse block.

Rather than tapping into an existing wire or borrowing a spare circuit from the factory fuse block, each CirKit Boss kit operates as a completely independent, relay-activated fuse block. A small trigger wire from any ignition or constant source activates the relay, keeping all accessory loads fully isolated from the factory electrical system. This isolated architecture shields bulbs, accessories, and sensitive electronics from the harmful voltage spikes that can result from a poorly connected power supply — a leading cause of OEM wiring damage and warranty concerns.

Key Features:

• Relay-activated circuit isolation — accessory loads remain completely separated from factory wiring and the OEM fuse block
• Constant and ignition-switched circuit options available across the product line to suit a wide variety of accessory types and installation needs
• Individually fused circuits powered through a heavy-duty relay for reliable, protected power distribution
• TXL cross-link polyurethane wire rated to 275°F at 600V for superior heat resistance and long-term abrasion protection
• Machine-terminated connections for consistent, corrosion-resistant electrical contact throughout
• Weather-resistant models available for under-hood and other exposed installation environments where moisture and dust resistance is critical
• Each kit includes an in-line circuit breaker, relay, relay/fuse block base with pre-terminated harness, and mounting hardware and terminals
• OEM warranty-friendly design — no cutting, splicing, or modifying factory wiring required

The CirKit Boss line is purpose-built for adding auxiliary lighting, electric fans, pumps, winches, and other high-draw accessories without compromising your vehicle's factory electrical integrity. Available in multiple circuit configurations — including 3-circuit and 7-circuit options in both standard and weatherproof versions — the CirKit Boss line covers every build from hot rods and muscle cars to classic trucks and serious off-road rigs. Backed by Painless Performance's reputation for American-made quality, every kit in this line is engineered to professional standards.