Hummer H3 Trailer Wiring | etrailer Trailer Wiring Harness Installation - 2006 Hummer H3. Today on our 2006 Hummer H3 we will be adding the Draw-Tite 4 Pole Hard Wire Kit Part Number 18252. Now to begin our install we'll first need to remove the rear tail light assemblies. Each tail light assembly is secured to the body with 2 Hummer H3 Trailer Wiring Harness | Advance Auto Parts Advance Auto Parts has 4 different Trailer Wiring Harness for your vehicle, ready for shipping or in-store pick up. The best part is, our Hummer H3 Trailer Wiring Harness products start from as little as $14. When it comes to your Hummer H3, you want parts and products from only trusted brands.