I recently repaired mine but eventually just replaced the entire thing. The problem is a metal on plastic relationship that is impossible to re-lubricate easily and an over-powered electric motor . Insted of a fuse blowing, the metal gear just snaps off or wears down plastic teeth.The rack may become stiff from lack of lube -ditto the 2 risers.
I found a cheap take-off from a later Cayman on EBay and modified it to fit.
Not a simple diy but doable