3-5 seconds then stop.. pause and run it another 3-5 seconds pause and continue till it's fully retracted.
This indicates somethign
First: If for any reason the landing gear got "Torqued" (Bent twisted) and is jamming it's placing excessive drag on the motor and causing the motor to overheat or the thermal self-resetting breaker to pop or the control to sense "Too much current" and shut down (I an trying to cover every variation on how these systems work here)
Also LUBRICATION it may just need lubrication.
With shore power present (or a portable generator) and the Trailer supported by other reliable means (Attached to ye old tow vehicle?) run it up and down and LUBRICATE a few times.. Also read the fine manual on lubrication.
IF this works, great
There are bearngs and thigs in the motor and gear box that can "Gum up"
That costs money.