[techie610]

I don't believe there is a 'minimal' draw requirement..
But with the statement of the stereo, I have to guess myself now.

Unless, you have a bad ground somewhere, and turning on the stereo might activate a new ground?.. Im kind of a little dumbfounded here.
If you have cleaned every grounding point, and filed of the paint, but it still does it, when its running, wiggle the light bulbs, pull them out, or twist them.
just be careful, as they get hot..
(^ Just so we can be 'Politically Safe.. lol)