JB4PRO Add On Harness B58/S58 FLEX

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Everything needed to make a confident decision.

Take your B58 or S58 build to the next level with the JB4PRO Flex Fuel Add-On Harness—the clean, plug-and-play solution for integrating an ethanol content sensor and optional fuel pressure sensor into your JB4PRO system. This harness keeps your installation professional, your wiring tidy, and your tune dialed to the exact fuel blend in your tank. Why it stands out: Plug & Play: Designed to connect directly to JB4PRO—no splicing, cutting, or guesswork required. Sensor Ready: Supports both ethanol content and fuel pressure sensors, giving your tune real-time data for precise fuel management. Clean, Reliable Installation: Includes 12 V adapter and inline fuse for safe, straightforward integration. How it works: This harness is the bridge between your JB4PRO tuner and your flex fuel hardware. It’s not a standalone system—you’ll still need a compatible ethanol sensor or flex fuel kit—but it ensures your JB4PRO receives accurate readings to adjust timing, boost, and fueling seamlessly for E‑series blends like E30, E50, or E85.