amp/head unit problem

my friend had one amp in his car going to 6x9's in the rear. we added anther amp to the front speakers, the problem is that everytime we kill power to the radio,(off button or ignition) and turn it back on, no sound comes out of the speakers. the radio and the amps do turn on though. but if we unplug the RCA wires from the new amp and then back in, it works fine. its just everytime you kill the power it doesnt come back by itself. the only thing we did to the head unit was disconnect the front speakers so we could run them to the amp. the plug for the first amp he had was one of those special plugs just for the jenson amp. so we spliced that into RCAs for the new amp, then come out of the new amp into a splice for the special jenson plug. we only did this because the old amp doesnt have any out puts. im also not sure where it gets the signal from the radio becuase there are no RCAs coming from it. it is a stock radio. some one put the first amp in so i dont know how they did it.

You should have used a Y adapter to split the RCA signal. But if you disconnect the amp for the fronts dose the rear one turn on with out any problems and vise versa?

I would have used a Y adapter but the jenson amp has a special plug and no RCA inputs for highs. when i disconnected the amp to the rears i still had the same problem, ill try it with the other amp. thanks for the help.

What is the model number of the jensen amp?