I haven't looked to see where the starter is at on mine, but if you can get to it, make sure the connections there are good. If need be, pour a like Coke over it. It can chew through a little corrosion (although your connecters get sticky - not sure if Diet Coke works)
You did say you are getting 12 volts to the starter, didn't you?
"...rationality of thought imposes a limit on a person's concept of his relation to the cosmos." -Nash
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09 Jetta TDI