2009 Chevy HHR OE Wiring Harnesses & Stereo Adapters Chevy HHR 2009, 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. 2009 Chevrolet HHR Car Audio Wire Harness Colors 2009 Chevrolet HHR Car Audio Wire Harness Colors. Car Radio Battery Constant 12v+ Wire: Red/White Car Radio Accessory Switched 12v+ Wire: Run a wire to the steering column and use the brown wire at the front of the center console on the passenger side.