Door Ajar light/Turn Signals Intermittant on/off condition

You obviously have a loose electrical connection somewhere. One way to find this is to sit down with a complete wiring diagram and go through it until you find one spot that affects all these circuits. This can require a fair amount of electrical knowledge because sometimes a misbehaving circuit can affect adjacent circuits. A good electrical technician has the best chance of finding it.

But your dealer is being honest. They pull their hair out about these things since they can be so hard to find.

I have had a couple of vehicles in the past (not Ford, but this can happen anywhere) that you would swear were inhabited by aliens. They kept running so I just ignored the pings and warning lights.