Alternator/generator/regulator problems of the 2011 Ford Focus

My vehicle has displayed an intermittent but increasing issue with electrical components. It started with a warning on the dash (including the warning chime) about a tire pressure monitor fault, and spread to include many and various warning lights. These include the parking brake light, and the door ajar light. When these lights are displaying, my turn signal indicator will not report on the dash, although I have been able to verify that the signals themselves are working on the outside of the car. Over time, this went from an occasional issue to being almost constant. At times, the tire pressure warning light will come on with constant chiming. I have experienced battery dead / non-start issues, although after jumping the vehicle, it will be fine for days. I have been able to get the dash to work properly by slapping the deck just above the display, although this only works for a short time. I typically only do this now when the constant chiming starts. I have had a mechanic look at it, and will be doing so again today. Last time, they tightened some wiring under the dash, and the issue appeared to go away for about 5 days, then crept back quickly. The initial thought was the alternator, although as mentioned above, the issue stopped after wiring was adjusted, and I suspect smacking the dashboard won't fix an alternator, or provide more power to dash lamps. Thank you. By the way, I am in canada, your form below doesn't offer that as an option.