I have an idea 'cause I've seen it, but can't explain it very well.
Typical OEM ignition switch had 4 wires coming down to a connector with 5 ports. The orange wire for lighting came down separately and was poked into that 5th port. About 5 years ago a bunch of aftermarket switches appeared at part stores with 5 wires. YEP, a big *** black wire for who knows what, from the switch to that 5th port. Nowhere left to poke the orange wire. Install it as received and that extra switched wire would connect to the cars harness illumination wire. It would toss a big voltage in the wrong direction and blow that fuse the instant the switch went to start position.
If you determine this is the case, what to do? Best to just leave that extra big black wire where it is so it's safe. Back the other wire out of the cars harness connector and make it to the orange wire outside/beside the original connector(s). Done
