{"product_id":"junruo-alternator-pigtail-with-inline-resistor-96in-4-pin-ls-iii-replacement-plug-and-play-for-105a","title":"JUNRUO Alternator Pigtail with Inline Resistor — 96in 4‑Pin LS III Replacement, Plug‑and‑Play for 105A","description":"\u003cstrong\u003eJUNRUO's ready-to-use 96-inch pigtail with an inline resistor converts a 12V feed into the correct alternator 'on' signal for 4-pin LS-series alternators.\u003c\/strong\u003e\n\n\u003cp\u003eThis plug-and-play pigtail replaces the factory 4-terminal flat alternator connector on GM LS engines and adds an inline resistor that steps down a full 12V ignition feed to the voltage the alternator expects for its field\/turn-on circuit. At 96 inches long, the lead gives extra reach for routing in custom installs, swaps, or older vehicles where the original wiring harness or engine control module (ECM) is not present or not used for alternator control. It's a practical solution for running alternators without dedicated alternator control wiring while preserving correct signal levels.\u003c\/p\u003e\n\n\u003ch3\u003eHow does this pigtail make an alternator work without ECM control?\u003c\/h3\u003e\n\u003cp\u003eThe inline resistor reduces the full 12V supply to a lower voltage that mimics the alternator's expected 'on' signal. This prevents over-voltage to the alternator's internal field circuit when the ECM or dedicated alternator control is absent. It effectively lets the alternator see the correct command voltage so it can begin charging and regulating as designed.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eBuilt-in resistor steps down 12V to safe alternator signal voltage.\u003c\/li\u003e\n  \u003cli\u003eCompatible with alternators lacking a dedicated control module.\u003c\/li\u003e\n  \u003cli\u003ePre-wired for immediate connection—no soldering required in most installs.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill this fit my GM LS engine and 4-terminal alternator?\u003c\/h3\u003e\n\u003cp\u003eThe pigtail is intended for 1999 and newer GM LS-series engines that use the 4-pin flat alternator connector. It matches the standard flat connector pattern used on many LS III generation alternators, including 105A units. Always confirm connector shape and pin count before ordering.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eDesigned for 4-terminal flat alternator connectors common on LS engines.\u003c\/li\u003e\n  \u003cli\u003eSpecifically compatible with 1999+ GM LS-series alternators.\u003c\/li\u003e\n  \u003cli\u003eWorks with 105A capacity alternators and similar configurations.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy choose a 96-inch lead instead of a shorter pigtail?\u003c\/h3\u003e\n\u003cp\u003eThe extended 96\" length gives flexibility when routing wiring across engine bays, swaps, or chassis where factory harnesses are modified or removed. It reduces the need for extension splices and lets you position the resistor and connector in a protected area away from heat or moving parts. Longer cable also simplifies custom projects and engine swaps where access to the alternator connector may be limited.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eExtra reach avoids additional extension splices during installation.\u003c\/li\u003e\n  \u003cli\u003eAllows mounting the resistor in a cooler, safer location.\u003c\/li\u003e\n  \u003cli\u003eSimplifies routing for swaps and custom engine bay layouts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat are the practical installation considerations?\u003c\/h3\u003e\n\u003cp\u003eInstallation is straightforward: plug the pigtail into the alternator's flat 4-pin connector and tie the other end into your 12V ignition or switched accessory circuit. Use proper cable routing, strain relief, and heat protection where needed, and ensure connections to battery and chassis grounds remain secure. For high-amperage systems, verify that wire gauges and fusing meet your vehicle's charging system requirements.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePlug-and-play connector fits standard 4-pin alternator sockets.\u003c\/li\u003e\n  \u003cli\u003eConnect to a switched 12V source (ignition\/switched power).\u003c\/li\u003e\n  \u003cli\u003eProtect wires from heat and secure with zip-ties or clamps.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for? JUNRUO's 96\" resistor wire pigtail suits mechanics, hot-rodders, and DIY enthusiasts performing LS engine swaps, replacing damaged alternator connectors, or installing alternators in vehicles where the ECM does not provide an alternator turn-on circuit. It's ideal when you need a reliable, off-the-shelf wiring solution that preserves correct alternator signaling without complex control modules.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can this pigtail be used with non-LS alternators?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: It’s designed for GM LS-series 4-pin flat connectors; confirm connector type and pinout before using with other alternators.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Do I need the ECM to use this resistor pigtail?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No—the resistor substitutes for ECM turn-on signaling, allowing the alternator to receive the correct on-voltage without ECM control.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"JUNRUO","offers":[{"title":"Default Title","offer_id":48084596818078,"sku":"B0CCJXQ9HZ","price":37.87,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/junruo-front-connector-4-pin.jpg?v=1785860470","url":"https:\/\/northtrailauto.ca\/products\/junruo-alternator-pigtail-with-inline-resistor-96in-4-pin-ls-iii-replacement-plug-and-play-for-105a","provider":"North Trail Auto","version":"1.0","type":"link"}