Last weekend my car suddenly shut off all power while driving home. It happened again this morning right as I was going to drive away. I could jiggle the key and it would come back on…but this seemed hokey, and unsafe (especially after my last stall on highway 17 due to a huge pothole and my inertia switch flipping). I realized the short was in the wires heading into the ignition switch, as I could jiggle them and it would turn the car on and off. I took the steering column apart and realized it was this little thing that went bad:
It is what gives the car 12 volts when it is “on”. I went to Bugformance at lunch and got a new one and installed it in about an 1.5 hours. I was really curious why the old one failed, so I popped it apart (which sort of broke it, which is why I had to get a new one):
It is hard to see, but in the above picture the copper contacts complete the 12v circuit when the car is on, and the contacts were literally worn away from the key being turned on so many times. In fact, the little copper plate was about half as thin as it normally should be at the locations where the contacts make contact. Inside the little housing it looked rusty, but it turns out it wasn’t rust but simply worn away copper dust.
So, after ~320,000 miles, the car’s ignition module wore away. Not too surprising for a car this old.