2007 Chevy HHR OE Wiring Harnesses & Stereo Adapters Chevy HHR 2007, Aftermarket Radio Wiring Harness by Metra®, with OEM Plug. For aftermarket stereo. Metra preassembled wiring harnesses can make your car stereo installation seamless, or at least a lot simpler. 2007 Chevy HHR Hitch Wiring | Harnesses, Adapters, Connectors Chevy HHR 2007, EZ Light Wiring Harness by Blue Ox®. The EZ Light wiring harness allows you to connect your RV to your vehicle’s electrical system in as little as 15 minutes. The EZ Light kit connects to the towed vehicle’s wiring..