Before you take the starter out, this seems obvious but most mechanics miss the simple stuff, disconnect and clean the battery terminals and connectors, disconnect the earth first then the positive, refit the positive, then the earth, make sure you have got your radio code(it will be lost), next check the earth lead that connects to the engine is tight and clean, check the positive lead to the starter is tight and clean, make sure the earth lead is disconnected from the battery before cleaning and tightening connections, there is a smaller lead on the starter solenoid (the small unit on top of the starter,)check this is tight and clean. Finally with your headlights switched on, crank the engine, if the lights do not dim and the engine does not crank, then the starter is not using any current you still have a fault, sometimes the small wire on the solenoid is not supplying good voltage, remove the wire and connect a test wire at least 5mm thick, briefly touch the positive lead, if the engine turns your supply to this wire is faulty or your solenoid is naff.
John jo, September 2006