I was digging around the engine of my car ('90 740 w/202k) while replacing the flywheel sensor cable and noticed that one of the braided copper grounds on the firewall was not connected to anything. There are two braided grounds coming from one screw in the top center of the firewall and one is going to a bolt on the top of the valve cover and the other is just floating.

Can anyone tell me exactly where this one goes? I've got a few manuals and searched pretty extensively but can't seem to get a good picture of what I'm supposed to be feeling for. I'm trying to sight with a mirror since there's no room back there but if anyone could give me a better idea of what I'm looking for it might help.

Thanks.