I have a 2005 F150 with a D3, Ipod, XM(T), cam and bluetooth. My dealer in Memphis did the bypass for me when he installed the unit, and everything worked great -- I could watch movies while I driv -- er, I mean, my PASSENGERS could watch movies while I safely drove them around. 
Now, I live in Dallas, so I set my traffic channel for the big D (224) and off I went. And yes, I'm subscribed to the correct services from XM to get the nav/traffic features for my P10XMT.
The problem is that after a couple of weeks, I noticed that traffic info (e.g., accidents, construction, etc.) had stopped appearing on the map and/or coming into play with navigation. I don't get traffic alerts at all, and Pioneer support says its because there's "a problem" with my ground wire connection for the parking brake. 
So first of all, does anyone else have a similar problem? If so, how did you address it -- a switch inline for the PB bypass so you could turn it on to watch movies and off when you weren't?
Thanks!