95 Cirrus Amp problems

I installed a pioneer cd/stereo player into my 95 cirrus lxi and when i turn on anything that is electrical(turn signals, map lights, fan blower, headlights) the stereo tunes into only the front two speakers on the dash, sometimes it is only momentarily(like when fan is turned up, headlights turned on) or will last the entire time(when turn signals are turned on) the 6 x 9's in the side and in the back go completely silent. This is very annoying while driving and even just driving the sound will cut out. I have racked my brain on this, i've rechecked the wiring and nothing seems to be working. It has something to do with my amp or maybe my amp connection, i just don't know. Any ideas would be greatly appreciated. Thanks.

i have the same problem except my front speakers r the ones that go out.

You would be better off running new speaker wires to all speakers and only having the power , memory and ground wires used from the original wiring harness.