Radio help
 

Hello just purchased a 2004 Boxster S and trying to replace the stereo. I ordered the wiring adapter that Crutchfield says is correct for my vehicle, the Metra 70-1784. I just have the front dash speakers and no navigation. To save money I ordered everything from Amazon so I can't call Crutchfield for help and I'm stumped.

The adpater is a large piece that the black and brown plugs from the car plug into but where I'm stumped is what do I do with the little yellow plug from the car? It was plugged into the stock stereo. I would up load a photo but even though it's the right format it won't upload.

I tried searching the forums but couldn't find anything that addressed this.