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Catastrophic ignition switch failure


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Haven't posted in a very long time, but I've had an incident worth posting a PSA about: the ignition switch located right behind the key tumbler failed quickly and with potentially disastrous results. I drove down for coffee in the morning and the car behaved oddly as I switched it off - the starter motor momentarily kicked in. When arriving back home, it did the same thing and also didn't want to turn the engine off until I jiggled the key. Thinking this was odd and would need to be looked into, but not taking it too seriously, my wife and I got out of the car. Luckily we needed to move some things over to the daily driver and were casually conversing when my wife side incredulously, "Fire!". There was a flame, like out of a lighter, coming out of the ignition right where the key goes in. I blew it out and disconnected the battery as quickly as I could. The smell was quite bad - anyone know what a RIFA capacitor smells like after exploding in an old power supply? I moved the panel underneath the steering wheel and found this. The whole switch assembly and wires were burnt and scorched. If my wife hadn't noticed the fire and we walked out of the garage, the whole car (and the garage and the daily drive) would have burned up. The hot wire from the battery isn't fused and will dump as much current as it can into that switch. Scary.


I did have a NOS ignition switch assembly from decades ago when I thought it was going out (turned out to be bad engine grounding) so I swapped in the new switch and cleaned up the wires and connectors and insulation. An easy fix for an almost total loss.


The moral of this story is if the ignition switch is acting funny, don't wait to swap it out. Something bad is about to happen.




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Wow looks like you caught it just in time!!!!


I had a similar situation happen on a car I was fixing for a friend. I had been having trouble with the ignition switch sticking but didn't think much of it, until I heard a snap and crackling like something sparking while turning the car on. When I turned the key to off sparks started coming out of the ignition switch followed by smoke. Luckily I haded installed a battery kill switch, so I was able to kill the power before a fire started.

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Scary stuff.  Thanks for sharing.  My cousin sent a video of a truck burning out on the street across from their house.  Apparently, the fire started on its own and ate up the whole front end before the firemen put it out.


I like stories that end with "so I grabbed a part out of my stash and fixed it."

I also like your heat shrunk crimp fittings.


I don't have a battery kill switch, but do keep a wrench handy.  It's stuck to the fender with a little magnet.





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23 minutes ago, '76mintgrün'02 said:

I don't have a battery kill switch, but do keep a wrench handy.  It's stuck to the fender with a little magnet.

That is an excellent idea!  How many of us still have their original ignition switch...and how many times has it been used over the car's life.  It's one of the few places other than the battery and starter motor where there's a wire that's always live and unfused....I think I have a spare 13mm wrench somewhere....and a magnet!



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21 hours ago, nv02 said:

if the ignition switch is acting funny, don't wait to swap it out.


When my original switch started acting funny @ 138k miles, I took it apart to see why the resistance was so high.

Discovered the small spring that holds the detent ball had broken.  I was lucky the loose parts didn't short-out and cause the horrific problem that you encountered.

Did you find the same?  Or was everything too melted?



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I hope my experience saves someone else from the same fate. I do have a fire extinguisher in the car as well. The failed switch was a molten mess of plastic, but I may try and deconstruct it one day. Still, hard to believe this switch failed after only 50 years 😉

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