I'd ask the same question. The way your message is worded it sounds like your ignition is always on, which is never a good idea. Typically when I pick up yet another old Volvo I find the dash butchered because someone has replaced what was probably a perfectly good coil and switch with an aftermarket setup. The dash damage comes from not knowing how to get the factory switch out. I always wire in a pushbutton, especially if the factory switch is in place. This eliminates the broken key scenario. The pushbutton is wired across the starter solenoid so when the key is on and the button is pushed the starter activates. Simple as that. Yes, the starter will operate with the key off but no engine start since no spark. I've been doing it this way for over forty years and it works properly every time.