Help with 2007 convertible / power door lock problems

[cwood2314]

Is there anyone out here who can offer some power door lock advice? I just bought an automatic 4.0l v6 convertible. One of a couple of problems I knew I would have to fix is a faulty power door lock. However, the deeper I dive into the diagnostic - the trickier it gets. For starters, my passenger-side power door lock works perfectly fine / locks and unlocks with either switch. The problem is within my driver's side. The door locks, but can only be manually unlocked. I swapped the actuator for a known good actuator - the problem persists. I swapped the driver-side switch for a known good switch - the problem persists. I went as far as swapping the entire door harness for a harness off one of my parts cars - and still, nothing has changed. I've checked and swapped everything, even things that didn't make 100% sense to check or swap. Any related fuses are fine. And I can't seem to find that the 05/09 Mustangs have an actual power lock relay anywhere. My last thought is tearing deep into the wire harness. Can anyone offer any advice? Where to look next?