Welp, I finally said the heck with it and ordered the $84 TFI module from Ford, himself; wife picked it up at the local dealership yesterday. Whilst opening the box, I thought, "Surely this part directly from Ford will be the 'real deal.' It will be Motorcraft branded." I thought wrong. It was another bunk generic-looking Motorcrap. "Well," I thought, "that sucks, but whatever. I'll pay $84 for the exact same thing that I got from RockAuto for $45 just so long as I FINALLY get one that tests-out." Busted out the 'ole DMM, ran resistance tests, and quickly determined that it's yet another dud. I will take it to AZ after work for more-definitive testing, but I'd bet $100 it will test bad like all of the others.
I'm at a complete loss here: 7/7 new TFI modules arrive DOA... How is that possible? I've racked my brain trying to determine if there's a likely explanation, but I have nothing. Here's what I've ruled out:
1. DMM works fine and has new batteries. Also used analog MM to confirm resistance results.
2. AZ Wells tester works fine; it is capable of passing a unit. It gave a passing grade to my original Motorcraft (branded) unit.
3. There is no disagreement between my resistance tests and AZ's Wells tester. So far, the results are 100% in agreement across 7 modules tested (6 duds plus my original).
4. It's not the brand. The 1st was a Standard T-Series, the 2nd and third were bunk unbranded Motorcrap, the 4th-6th were branded Motorcraft, and the 7th was yet another unbranded Motorcrap (much to my surprise).
5. It's not the vendor. The 1st was from LMR, the 2nd and 3rd from RockAuto, the 4th-6th from some rando on Ebay, and the 7th from Ford, himself.
Going WAY out on a limb here... Could it be possible that the new module needs to be installed and go through a sort of "break-in period" before it will give valid results when tested? I think that this really makes no sense--internal shorts/bad connections don't fix themselves through use--but that's really all I can think of. I guess what makes me think that that's even remotely possible is that it's probably quite uncommon for ppl to have brand new units tested, so maybe the "break-in-before-valid-testing" issue never really comes up?? Then again, the manufacturers claim that they test all units before they leave the factory, so that would rule out my hare-brained "break-in" theory. At any rate, I'm still assuming that it's because of something that I'm missing rather than a widespread conspiracy to sell defective TFI modules to the unsuspecting public...
Does anyone have other theories?
... I'm thinking I'll order a Wells unit from RockAuto and see how that goes. I heard they are pretty well-respected for their ignition parts..