Looks like you probably need this: http://www.crutchfield.com/p_607SCC1...nly-Tuner.html

And if your truck has a factory XM/Sirius antenna, you could probably buy an adapter to plug it into the module.

The wireless signal strength is probably just a general thing, and shows for the FM or AM or WB signal as well, and doesn't necessarly have anything to do with the satellite if you haven't got the module/antenna.