fosgate amp 12v at speaker output

The car is a 05 Grand Prix w/ a Rockford 125.2  Hey guys,sooo i get a call today. Customer wants my insurance info...Kind of perplexed,I asked why...Customer states that an amp install from about 1 1/2 years ago  has fried his ignition and wants our insurance to pay for it...Immediately we go up to the dealership and ask what the problem is ...The service manager and the tech both greeted us at counter...Said amp is producing 12v through the remote lead and that it kept the ignition on at all times which fried the ignition relay...We asked how they checked this...And the tech says that he used his testlight and there was only 9.6 volts and 0 amperage on the remote lead. So then they refuse us access to the car...After a few minutes on the phone,we spoke w/ the district service manager that gave us permission to look at vehicle...At this point we turn around and head back to the dealer...they said they had not touched anything at the amp and are awaiting our arrival...As we are walking in the service manager is walking briefly the other way w/ his meter in hand...Walk up to vehicle...Ground is off the amp...Remote lead is disconnected...Go through whole install and everything appears to be fine...(my tech did use pink in ignition harness for remote turn-on) We explain that the install is fine and hooked up properly.That either the malfunction happened at the amp(not our amp) or in the ignition itself...After looking at install i start getiing kinda wized...The tech that disconnected the remote lead apparently just grabbed and pulled b/c the remote lead had about an inch and a half of wire exposed tucked underneath the carpet(luckily it was stuck to the padding and did not touch chassis) After a little trickery(backwards questions) we finally get out of service manager that the tech had touched bussman fuse on the 4 gauge to the sway bar underneath the hood...After that they replaced the fuse and when they were parking the car it would not shut off w/ key...DIRTY DEALERSHIPS...So after that horribly long post my main question is what do you think caused the amp to have 12v on  remote lead,speaker leads...What in the amp would cause this to happen. I am assuming that the touching of the fuse holder did something to the amp...The service manager apologized for the confusion and shook our hands...Eagerly awaiting your responses. Thanks guys...Im sure i have left out several parts of the story...

PS...The dealership has had the car for 3 weeks and that all they had to do was replace ignition relay...Bill  is $800.00...I guess i do not know what all goes into replacing a ignition relay in a 05 grand prix...But $800.00...Ya think the dealer is exhausting all options to get this ticket paid...!!!!!

Is there 12 volts on the remote wire and on speaker terminals of the amp.  If so that seems as though the amp does not have ground.

Would this cause the amp to send 12v out to ignition...??? And if dealer left the ground disconnected,and rca's left plugged in... Do you think that it could damage anything on the factory radio(used a PAC LOC).Or b/c of the reading it is not seeing any ground...So probably no damage to radio

In an older car, probably not.  On that Pink wire, probably so.  The Pink wire is basically a control wire for the computer.  It has a very high resistance.  An older car, the ignition wire actually powered ignition components.  They require more current than you are able to pass through the tiny componints between battery and remote terminals of the amp. 

Yes you need to go back to the dealer and reconnect the ground wire.  After you do this and determine that there is no voltage getting to the remote terminal, ask the customer if the amp was playing when he brought the car to the shop.  If it was not playing, it could have lost ground.  If he rode with it like this for any amount of time, this could have caused his failure.   Remember to tell them that some Idiot helped you figure it out.