Whinning sound from rear speaker

Last year i installed Alpine type S component speakers in the front doors and Type S coaxial speakers in the rear doors. They are being run off a Alpine pdx400 watt amp. i also have a pdx1200 amp running 2 jl audio 10s. This is all coming from a stock head unit.

 

Now for the problem my amp for the speakers shuts off when i'm listening music at a normal volume. The subs work fine but the speakers dont work at all. Once i restart my car everything works fine for a while until it happens again. The amp is not overheating.

 

Also my rear driver side speaker makes a whinning sound that get higher as the gas is pressed more. i used the original wires when i installed these. is it a bad ground wire? maybe from the amp? are these problems related?

 

Any input would help thank you.

The speaker whine is caused by a ground loop of some sort, but I don't remember at the moment what conditions would cause only one speaker to do it. Check all of your connections for that speaker and also for your speaker amp. Make sure the speaker wires aren't grounding or shorting anywhere and that your amps' grounds are solid and connected to bare metal.