I had a similar problem with mine a few months ago. It acted as though the motor may have been overheating and would stop. Wait a few minutes and it would continue to retract until fully retracted. It deployed just fine. Took it in for other service and had the tech look at it. Added two or so turns on the internal spring and works like new now. Had nothing to do with power, just needed to have the spring tension increased a bit.
Tom and Barb
'07 Winnebago Voyage 35L
Workhorse W22 chassis FMCA 219315