Twin Headlight & Relay Wiring Loom Harness (H4 H1 Upgrade) Holden HX HZ - WK1023

If your classic is suffering from dull, yellow headlights, the issue is often tired factory wiring rather than the globes themselves. Designed primarily for Holden HX and HZ models fitted with factory twin headlights, this Twin Headlight & Relay Wiring Loom Harness delivers full battery voltage directly to your lights — restoring brightness and protecting your original switches. By bypassing aged wiring and routing power through high-quality relays, this setup is especially important when running higher-wattage globes (100W+), which can otherwise overheat and damage factory wiring and headlight switches.Solves Dim Headlight Issues: Draws power directly from the battery rather than through ageing factory wiring, significantly improving light output.Dual Relay Configuration: with one relay for Low Beam, and one relay for High Beam, this ensures stable voltage delivery and reduced load on original switches.Plug-And-Play Operation: Designed to piggyback off your original headlight plug to trigger the relays, requiring minimal cutting or splicing of the factory loom.Supports Standard & High-Wattage Globes: Compatible with H4 bulbs (High/Low Beam), H1 bulbs (High Beam), suitable for both standard and higher wattage applications.Heavy-Duty Automotive Grade Wiring: Utilises thicker gauge cable to safely handle increased current draw.Inline Fuse Protection: Typically includes inline fuses to safeguard the new circuit and electrical system.Protects Factory Switchgear: Prevents overheating, melting and premature failure of original headlight switches and wiring.For Holden owners wanting brighter, more reliable headlights — especially when upgrading to higher-wattage globes — the Twin Headlight & Relay Wiring Loom Harness is a smart and protective upgrade that improves visibility while safeguarding your factory electrical system.