2000 Taurus Wagon Liftgate - Door Unlock

Using the key fob or the door switch to unlock all the car's doors,
the liftgate power door lock no longer works.

Fuse checks out, so does the relay I tested it with an ohmeter and
with 12 volts, works great.

I picked up a used door lock motor from ebay for the liftgate and
swapped out the original, but still no lock/unlock.

Haynes has a diode shown in their wiring diagram for the liftgate
power lock but alldata does not. I figure if there is a bad diode in
the circuit that's my problem.

Any other ideas? I'm running out of them.

Thanks!