My 900 commemorative convertible exhibits the following symptoms:

1. When starting the car, I'll turn the ignition key and nothing
happens - no dash lights, etc.  I'll keep turning it on  & off until
finally lights come on and it starts.  During this process, I'll flash
the high beam stalk to see no lights whatsoever.

2. When driving, I step on the brake and headlights will "blink", the
radio stops momentarily.

The ignition switch has been replaced, which seemed to alleviate the
problem for a week or two, then the symptoms (lights blink w/brake)
reappear.
Any thoughts/suggestions would be GREATLY appreciated.

Thanks!