Okay, so I had my iPhone’s Sleep/Wake button replaced. But ever since I got it back, the Maps app would always indicate an incorrect Current Location except when connected to Wi-Fi. In other words, the GPS was not working. I tried restarting, resetting Location & Privacy settings, resetting Network settings, resetting All settings, and a complete restore (downloading a fresh copy of iOS 7.1.2 and installing that). Nothing fixed it. A software restore virtually eliminates the possibility of a software fault – the hardware must be the problem. So I called Apple’s support and they set up a Genius Bar appointment at the nearest Apple Store for somebody to look at my phone and see what’s up.
Don’t tell anybody this – just before the appointment, I was so curious to know what was going on that I opened the device by following iFixit’s guide – and found a missing GPS cable! The fellow who had repaired my device had forgotten to reinstall the GPS antenna interconnect cable, so my iPhone was unable to receive correct data from the GLONASS satellites. No hard feelings. Apple replaced my device with a new one, and that, of course, solved the problem.
In the fuzzy photo I took, check out the missing flat black cable. There are supposed to be two, one running on top of the other, that connect to the logic board inside the iPhone. Note the fact that, below the slightly longer connector, there’s no connector!