[frank.koetter]

I have a similar problem and seems to be a relay panel or switch, have not chased it yet, the cord will retract but not extend.  
I have found that I can pull the cord out manually by forcing it in and out slightly. the motor will disengage and the pully will turn with a little difficulty.  switch seems to be the most obvious place to start, but the relay box is relatively accessible/well labled and inexpensive.

I'm not sure if you solved your problem.  But what you're describing sounds like the cord is pushing against the "safety actuator switch".  It's located above the round bin and is the assembly of 4 white rollers the cord runs through.  The rollers are spring loaded and when the cord pushes too hard against a roller it pushes against the actuator switch and turns off the motor when you try to extend the cord.