Weird - it's a turn-y switch - it rotates into or out of contact by pressing the button. That little black disc (brass contacts on the bottom side that I didn't take a pic of...) gets turned by the shaft above it. So, it needs to turn freely, have an undamaged top side (the little ramp, triangle thingy's), and the entire mechanism needs to slide / move freely, and all the contact brass needs to be clean. I didn't notice any old grease or lubricant in this one. I was surprised that the "top" was just held on by a couple of clips on either side. Everything is PLASTIC and we don't have very good luck with PLASTIC here in the DESERT, so I was a little nervous. I heated the whole thing up a bit and used an extremely small screwdriver to pry one side at a time. First side was pretty easy - the second was quite a bit harder but eventually the "top" came off and revealed the underlying surprise. The switch is indeed simple and you can test continuity straight through on the rivets both sides or the brass the rivets tie down. Also check continuity through to the bulb holders to make sure corrosion hasn't killed the circuit between the switch and the bulb.