Thanks Ron! I had already printed your helpful DIYs in color! For the rattle, the dealer's diagnosis was the passenger cats but I couldn't find or feel any cracks. I will look again in more detail.

It could also be the exhasut manifold. I had a car once where the exhaust manifold failed. It's starting to sound eerily similar. I'll check that too.

As for the harness, I already bougt the harhess at the dealer's gouging price ($50 or so) and will follow your step by step instructions.