[s-cars] weird electrical behavior

[Lee Levitt]

My son's '97 A6 is showing some weird electrical behavior.

Intermittent failure of tach, directionals and HVAC. Flashers 
work, other electrical items work.

Now here's the really weird thing. My wife is away for the weekend 
and calls to report that the wipers and HVAC on her '96 A6 are not 
working.

14YO daughter does the laying on of hands and now the wife's car 
is working again.

The two cars park near one another, but not close enough to pass 
viruses directly. One's inside, the other's outside.

So, here's my question. Are there any known points of failures 
that take out multiple electrical items on the C4 cars? Fuses and 
relays are not common to the failed items.

Thanks!

Lee