[hofffam]

First of all your dealer sucks. It sounds to me like they did NOT replace your headunit. It seems like the radio code would be the clearest way to tell. I agree that it seems highly unlikely they would have restored all your radio presets.

It is possible that replacing the speakers caused a problem as Bobpres said above. If somehow the new speakers have an erratic short it could trigger the headunit's protection circuitry and shut it down. I doubt it is water. Water is way overrated as a conductor of electricity.

We don't know how the headunit's circuitry works. It could be that if it detects a fault in any speakers all of them shut off.

I would do this:

1. Double check all wiring to the replacement speakers. I assume you used plug-in harness adapters. Check them thoroughly. If you did not use adapters check all your splices (etc.). Check that the speaker terminals are not hitting the door frame and causing a short when you mount the speakers.

2. If all is OK with the wiring, disconnect the rear speakers and run that way for awhile. If all is OK, then you may have a problem with the rear speakers. Repeat with the front if necessary.

3. If none of this works - verify your headunit was replaced or not. If not - pound on your dealer.