QuandAns42

Hard to say if it's the cluster itself, or another module sending the cluster bad data. I'd recommend calling the folks at https://www.instrumentclusterstore.com/Ford_instrument_clusters.htm to help you diagnose the issue. That's literally their whole business so I've had really good luck getting quality help from them in the past.

Keep up the process posts! I really like your "nothing permanently installed" approach. It's a metal tent! However, I think insulation is really a necessity, and should probably be one of the earlier steps... do you have any plans in that direction?