I posted earlier this afternoon that I had solved the radio whine
problem. I though I had. I had tested it with engine off and on BUT I
did not have the antenna connected. When I re-installed the unit the
whine was back when engine running.

To say I was chagrined is an understatement. Back to it, checking
ground sources when I noticed that the unit would remain on even with
headunit ground removed, and even with head unit out of mount. It was
grounding through the antenna.

Antenna disconnected and main ground wire reconnected, no whine when
engine running.

So now I have determine if that kind of grounding through antenna is
normal, or a fault.

alistair