I didn't know the unit needed to be coded for a car. We must assume that hasn't been done. I need to buy a cable for NavCoder, right? What needs to be recoded?

I'll try the downgrade and upgrade process and get back to you.

I wonder if it's one more thing. I don't have the GPS cable hooked up yet. I have an e39 touring which, it turns out, doesn't have the Trimble unit in the same place as the saloon. I had to order an extension cable. Of course it has to come all the way from Germany and will take a month to get to the States. Anyway, could that be the problem?