Speartech STE-GEN4-6L80 Gen IV LS 58x Standalone Wiring Harness Kit with 6L80E Transmission

The Speartech STE-GEN4-6L80 is a built-to-order, plug-and-play standalone wiring harness package engineered specifically for Gen IV (58x) LS engines paired with the 6L80E or 6L90E six-speed automatic transmission. Designed to simplify LS swap builds, this harness interfaces directly with all engine, transmission, and emissions control sensors right out of the box—no splicing, adapters, or extensions required.

Every harness is custom-built in-house at Speartech's facility and test-run on a live engine and transmission setup using a GM Tech 2 diagnostic scan tool before shipping. Once it passes all diagnostic checks, the harness is wrapped in Speartech's exclusive heat-resistant woven fabric covering for a clean, professional finish. The standard harness measures 42 inches in length, originating from the passenger-side rear cylinder head and running to the ECM mounting location.

Kit Includes:

• Engine Main Wiring Harness
• Transmission Main Wiring Harness
• Engine ECU (Engine Control Unit)
• Transmission TCM (Transmission Control Module, if applicable)
• MAF Sensor with bung
• EVAP Canister
• Pre- and post-cat oxygen sensors
• Drive-by-wire (DBW) compatible accelerator pedal
• OBD2 port with integrated check engine light output
• Firewall grommet
• Full installation instructions with every wire individually labeled

Key Features:

• Plug-and-Play Design: Fully compatible with all Gen IV 58x LS engine and 6L80/6L90 transmission sensors—no modifications needed
• Live Engine Tested: Each harness is run on an actual engine and transmission using a GM Tech 2 scan tool prior to shipment
• Heat-Resistant Woven Covering: Durable fabric wrap protects the harness and provides a factory-quality appearance
• OBD2 Diagnostic Port: Built-in OBD2 port with integrated check engine light makes future diagnostics straightforward
• Supports 6L80/6L90 Tap Shift: Optional TCM reprogramming available to enable paddle/tap shift functionality
• Fully Labeled Wiring: Every wire is individually identified for simplified installation and troubleshooting
• Custom Layouts Available: Non-standard ECM placement, supercharger setups, high-ram intakes, and other configurations available upon request

Compatible Gen IV 58x LS engine variants include the LS3, L99, LS7, LSA, LS9, and 5.3L/6.0L/6.2L Vortec truck engines. Optional add-ons include front O2 sensors, MAF sensor, and a 6L80/6L90 tap shift module. Custom harness lengths and layouts are available by phone order for an additional fee.