The electrically-operated sunroof on my Mk3 (1995) VW Golf has trouble operating under its own power. When I push the button to open/close it, it moves a fraction of an inch and then gets stuck, with something in the circuit making an audible "click" noise. It is possible to open/close the sunroof all the way by pushing the button dozens of times in quick succession.
What's a good way to investigate / fix this? Does it just need some kind of lubrication, or is there a problem with the circuit? (The click noise makes me think that something is overloading, or ... something.)