Glad you found the problem! Nice job! Physically making the repair on the wiring harness is the easy part. It's the symmetrical logical approach that takes time but it's well worth your effort. Thanks for reporting the fix, many do not which is not helpful for this forum community education...
My thoughts after reading this is a wiring problem. A lot of parts have been thrown at it including the PCM which is what most mechanics do first because it's easy and not their money. The first thing I would do is to get a wiring diagram for your vehicle to see what feeds the sensor heaters...
Todd I just received the 2 Austekk Aluminum T stat housing that I ordered from you. It was very fast and painless making for a great experience. They look beautiful and are well made and additionally they make the original Motorcraft T stat housing look like junk. I am happy I decided on the...
The late model engine swap has been done before with a newer low mileage Ranger engine. On the other larger explorer forum you can find others who have done it with great success and no problems.