2010 Ford Flex Power Liftgate Won't Open or Close, SYNC Stops Working

If you have the following symptoms with the power liftgate:

• With liftgate closed, try to open it with the liftgate buttons or the keyfob.  The gate will open about six inches, and then give up, slamming shut.
• When open (manually), the gate will refuse to close from any of the liftgate buttons or the keyfob.
• When closed (manually), the gate will refuse to latch completely.  (You will not hear the latching sound you normally hear when the gate is closed).
• Driver information center indicates that liftgate is open when it is in fact closed.
• Interior lamps stay on when all doors are closed because it thinks the rear liftgate is open.  (The lamps will shut off after driving away.)
• Workaround:  Rotate the instrument cluster dimmer to the lowest position, until it clicks -- this will force all of the interior lamps off.  This is also useful if you're tailgating and you don't want the interior lamps on.

It seems that it's possible that the liftgate can forget the learned open and closed points.  It even mentions this in the manual.  See this post on the Ford Flex forum.

At the same time this issue happened, the voice command button on the steering wheel (the button for SYNC) stopped responding.  My phone would not detect the SYNC Bluetooth connection and for all practical purposes it seemed that SYNC was not working at all. 

The solution to both problems:

• Close the liftgate manually.  
• Disconnect the battery for 20 seconds.  
• Reconnect the battery.  
• Make sure the power liftgate is enabled in the vehicle setup.  
• Start the vehicle.
• Open the liftgate with the keyfob or any of the liftgate buttons.
• Wait at least one minute for SYNC to boot up, and see if the voice command button starts working again.

I may have gotten lucky, but this solved both the SYNC issue and the liftgate issue in my vehicle.