sounds like plastic gear parts up in the roof. The nylon parts get wore easily since they are in the roof and subject to extreme temps. If any of that mechanism fails then your sunroof will stop working even if the motor is still good. The fix will be to remove the headliner to get at the mechanism and then identify the culprit and replace it. The dealer will have the lil gear thing and it will be cheap. Good luck !!! I just finished this: took out headliner-parts-belts, etc.. The little plastic relay was clicking but it did not make sense motor was burnt out. I tested relay with meter and crossed the leads. The roof motor started to hum. I fiddled a minute and off it went. Running like a top. I think it was winter corrosion built up. BOTTOM LINE: fiddle with the relay first, then attempt the motor removal.