I have a 2015 Focus that I tow and did have a similar problem. Every now and then I would go to start and nothing. Would turn the disconnect switch and it would start. Re checked my connections and tightened them all up and problem solved.
Just before last service it tossed a CEL light. Had my dealer check it out when service. They found code, long forgotten, and said it was a generic code for unspecified (electrical?) issue. Said there was a voltage drop across my disconnect switch. As he went on he asked "Why do you have a disconnect switch? I told him it was because Ford requires it to flat tow. His reply made NO sense or logic. "Well, wait about two hours before disconnecting it. It is because the computer takes about two hours to shut its self down." I told them to show me that part in the manual or a service memo. I"m still waiting. Plus he couldn't say how much voltage drop was across the switch.
I have the well known transmission problem that comes and goes, with the clutch pack and software up date. Again it is getting to the point of bugging me, getting close to bitching about it again.
I never have changed or re-did the switch
The service writer is new but has about 10 years Ford experience.
It may have well been my last visit to the dealer and I have been using them since 2001. Plus he did some other stupid stuff that I figured out later.
I thought about contacting the service manager but I figure this guy will be down the road soon enough.