96 850 Hot key in ignition, solved

[JimBee]

It was the key switch. I swapped in a used one from inventory and so far all is good (after one day). Even with the ignition off and the key out, the switch stayed hot constantly. I'm guessing that 850 has around 200k.

What's puzzling about it is the key was so hot that holding the blade part would burn my fingers—yet, none of the wires to the key switch were even warm. There was so much heat generated that the block of metal under the steering column that contains the key cylinder was just as hot as the cylinder and key, so that would seem to indicate a heavy drain.

I disconnected the negative terminal of the battery before pulling the key switch, and just slightly retouched the cable to the negative terminal to see if there was a spark. At first, there was a tiny spark, but then when I tried it again several times, no spark.

That leads me to wonder, if there is enough resistance in the key switch to heat it up like that, why is there no obvious drain at the battery, OR why aren't any of the wires at the key switch even slightly warm?

Any thoughts?

[abscate]

10 watts of heat into a small piece of metal will warm it up nicely but barely load the battery. It gives you some respect for how much energy is stored in the battery which is about 1000 watt hours

[JimBee]

So if the switch resistance became a direct short circuit, pulling the full force of the battery's capacity into that wire and the switch there would be smoke and flames. But does this switch condition ever get to that point? I googled the hot key question and quite a few others have over the years posed questions about it, but I didn't notice reports that any of the overheated switches got to catastrophic temperatures. It makes sense though that left to progress, it could happen.