Nexus LS 4 Pin Delco Alternator Harness Size: 200

Overview

The Haltech Nexus LS 4 Pin Delco Alternator Harness eliminates alternator wiring headaches in LS swaps and GM builds. This plug-and-play pigtail connects your Delco-style alternator directly to the Nexus R5 Universal V8 terminated harness, giving you proper charging system control without splicing or bodging connections.

Technical Specifications

• Part Number: HT-186124
• Connector Type: 4-pin Delco alternator plug
• Wire Length: 200mm
• Application: Nexus R5 Universal V8 systems
• Construction: OEM-spec terminals and sealing

Why You Need This

Every LS swap or GM build using a Delco alternator faces the same wiring challenge — how to properly connect the alternator's charge, sense, and field circuits to your Haltech ECU. Without this harness, you're left cutting and splicing the main loom, creating potential failure points and warranty issues. The 4-pin Delco connector handles the alternator's L terminal (field control), S terminal (voltage sense), and B+ charging circuit, ensuring your Nexus ECU can properly regulate charging voltage and monitor system health.

This becomes critical in high-performance builds where charging demands fluctuate dramatically — from idle to wide-open throttle with electric fans, fuel pumps, and ignition systems all drawing power. Poor alternator connections cause voltage drops, erratic charging, and can damage sensitive ECU components. We've seen too many expensive ECU failures traced back to dodgy alternator wiring that could have been avoided with the proper pigtail.

ECU & System Compatibility

Specifically designed for use with the Haltech Nexus R5 Universal V8 terminated harness (HT-186200). This pigtail integrates seamlessly with Nexus R5 ECUs managing LS1, LS2, LS3, LS6, LS7, LSX, and other GM V8 platforms using Delco-style alternators.

What's in the Box

• 200mm 4-pin Delco alternator connector pigtail
• Pre-terminated leads for Nexus harness connection
• Weather-sealed connector housing

Complete Your Build

Most customers fitting this alternator harness are building complete LS swap packages. You'll need the Nexus R5 Universal V8 terminated harness (HT-186200) that this pigtail connects to, plus engine position sensors, throttle body connectors, and injector harnesses to complete your install. Our team stocks the full Nexus ecosystem and can guide you through the complete wiring solution for your specific chassis and engine combination. Contact us for pre-sales advice — we've wired dozens of these setups and know exactly what works.