I'll try and get a photo tomorrow. However, besides the two cardboard insulators, there are four basic components to the safety switch: 1) the base (with two screws for the wiring); 2) the switch button itself; 3) the slide rivet (which supports the button); and 4) the slide spring (which causes the button to pop up when the nozzle is taken off). I think the primary thing that wears out in the switch assembly is the base. It has two contacts that get loose over time and will spread too far out. When the button is depressed, the little brass rivet in the button can't make contact in order to close the circuit that will then send electricity to the motor. So the switch base is the most likely culprit. Luckily, those parts are available from Kirby. If that doesn't work, then you'll need to get into the motor. The first thing I would check is to make certain the motor field clips are connected to the brush holders. If they are, then I would get a multimeter and test the continuity on the motor field. If that tests out OK, then I would test the continuity of each field on the armature. I think you know all that. But if you have a bad segment on the motor field OR the armature, then you'll need to replace the whole motor.