Do you get boot issue when open door with key in the door or just with key fob? I suspect key switch in that case.

The FSU is directly below the head unit of the radio. Accessed from the right side of the transmission hump under the dash. Find a YouTube video basically you pull off the carpet panel right side of transmission hump and it's pretty far forward against the firewall.

It has a big molex connector and unplugs. You'll see why people call it the hedgehog when you see it.

If the spikes are conical it's original and way overdue for replacement the new ones have many more spokes and they are cylinders.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)