Need help with install, No sound!

[Rectorna]

I sold my amp to my friend to run his Infinity Kappas Active in his 2005 Subaru Legacy GT.
He had been using the Kappas up front passively for awhile but he does not have a sub right now so we had the bight idea to go ahead and run them actively since the amp I sold him (JBL MS-A1004) has built in line in convertors and has on board digital crossovers. We got both sides installed and all the wires mounted and turned on the amp and set the crossovers and everything looks good.

We go to try on the car and try to play some music for the first time and there is no sound coming out of ANY of the speakers; even none coming out of the rear speakers that we have not touched.

All we did was added speaker wire to the factory wire that was in his door and ran it to the line out convertor on the amp. Did not touch the head unit or any other speakers in the car at all. just the front door wires. The amp works fine and we have checked all the fuese and all of them work so we are completely stumped.
We could understand if the front speakers did not work since maybe we had a wire mixed up but we do not understand why none of the speakers in the car work now. The head unit powers up fine but does not output any sound.
We can not tell if there is a factory amp in the car or not, we have been told different things.

Any help would be great!
Thanks!