So, it was connected to the G port on the CPU and I tried it on the GPS port on the RG3 and nothing changed. As luck would have it, I was sent two GPS antennas and so on a whim I decided to just plug in the other GPS antenna instead and see what happened and it works fine. Apparently the first GPS antenna is bad (I've now swapped it back and forth with the other antenna and it keeps failing when I try the original). So, thanks for all the help!

I still can't get the audio sorted out with the ALPConnect app. I ALWAYS want the ALP to alert via the HiFi module, no matter what. However, when I connect with the ALPConnect app, the audio appears to always get rerouted to the stereo in the car, which means I get no audible alerts at all UNLESS I also happen to be using my phone as the audio source for music (my stereo is set to NOT put audio alerts from my phone over the car audio unless the phone is the music source, which is how I want it). Is there some way to force the audio out of the ALP HiFi speaker always?