Final Update: RonD/Adsm, you are the men. Yanked the alternator, took it to AutoZone #1. They don't have the patch cable to test it. Really? For an F-150? Down here, that's like every second vehicle down the road. Took it to O-Rileys. Both of their patch cables are broken. Took it to AZ #2 and it was only putting out 11.4 volts - which is the exact thing RonD told me to check and their numbers line up with mine. O'Rileys said my battery was good, AZ said it was weak. I replaced them both. I really couldn't believe how easy it was to do. All I really needed was a 10 mm socket, an 8 mm socket, a Phillips screwdriver (which in retrospect, I didn't need at all), a flat blade screwdriver and a 1/2" breaker bar to take the tension off of the serpentine belt. If I hadn't been running around to half of the auto parts stores in town, it would have been easily < 1 hr. I even put it all together with a flashlight under my arm. Anybody seen my trouble light?