Amazon: h4 wiring harness Amazon: h4 wiring harness. Skip to main content. TOMALL H13 9008 Male to H4 9003 Female Ceramics Retrofit Extension Wiring Harness Socket Adapter for Jeep Wrangler JK TJ LED Headlight Conversion Kit 12cm(5inch) 4.2 out of 5 stars 19. $9 $ 9. 99. Get it as soon as Mon, Jul 22. H4 Upgraded Headlight Harness - K Suspension H4 Wiring Harness Upgrade for any vehicle with the H4 light plug Increase your OEM lighting output by a minimum of 50% (usually more)Save your light switch from burning up like they always doTake the load off the system and wire your lights directly to the battery!Plug 'n Play designNo wiring needed Watch our video below for some guidance on how the install will go!