Considering the evolution of the problem and building on what
@murcod has posted above (which IMHO is a good general description of the system overview) ....
The root problem could lie anywhere between and including the wiper switch on the steering column, the BCM, the SASM, the left (master) wiper motor assembly and/or any of the interconnecting wiring including various power feeds.
The vast majority of the wiper system DTC's are used to guide specific further diagnostics tests ("pinpoint tests") intended to reveal the specific component or control logic failure causing the problem. While some DTC's point to a specific 'component replacement corrective action', most point to a likely trouble-spot with further tests using the Ford Diagnostics Tool to refine the problem identification and thence finally to a corrective action.
The 'magic' of the Ford Diagnostics Tool is that it serves both to provide electrical circuit/signal testing capabilities similar to a high-quality multimeter + oscilloscope
and to
interpret and report computer logic signals in a way useful to solving problems on Ford vehicles specifically. It's worth noting that this tool, which is far from inexpensive, is available to independent shops as well as Ford dealers.
In plain English: Even with Focccus and/or Forscan, lacking the further capabilities of Ford Diagnostics Tools to run pinpoint tests, IMHO it's unlikely that you'll be able to efficiently or effectively diagnose the root problem. IMHO you'd still be left with hopeful 'parts swapping' with a certain degree of hit-or-miss success (and the potential wasted expense that goes with that).
This is, unfortunately, a side-effect of cars using sophisticated logic control for these systems rather than 'old fashioned' electro-mechanical systems; that makes it very difficult for even very competent mechanics to diagnose and solve such problems efficiently with 'traditional' tools.
IMHO this is a case where a Ford dealer
or an independent shop using Ford Diagnostics tools or their equivalent, applying the trouble shooting procedures applicable to this system,
may well yield your most cost-effective solution. You are not 'captive' to Ford dealers** ... there are independent shops that have equivalent capabilities and may offer more competitively-priced services than a dealer.
**Though IF you have any potential Ford warranty coverage, only work by a dealer can provide that.