What were the symptoms that led him to believe it was grounding out?

I am getting constant feedback from the system. I get noise at low volumes
and
when a door is opened while the system is on, I get a massive, strange
noise
through all the speakers. Somehow he traced this phenomenon back to the
tweets,
but god knows how he made the decision that it's grounding out. Replacing
the
Zapco 350 he sold me with a new one made no difference, the deck is not
causing
the noise, and neither are the crossovers. I'd really like to get the
tweets
replaced (I think they're damaged) but I don't think he'll do it, and come
to
find out that he already modified the first pair (without telling me!!) so
I
don't think that Dyn will honor a warranty claim on them. I'm screwed,
I've got
no cash to replace this system and he refuses to do it.

Sounds like yet another installer nightmare. I hate it when they cut up
your speakers, without even clearing it with you first.

First, the noise when you open the door. You've made sure it's not
correlated with the interior lights, right? What happens when you wiggle
the tweeters in place? Go over bumps? What about the midrange speakers?
Has he checked those, to make sure they're not grounding out either?

See what he can do for you, I guess. But be prepared to do it yourself if
you want it done right.