This is my first time posting on here.
I have a 1991 mustang 2.3L.
I recently hooked up two 10" subs with a 240 watt amp. The power wire is run on the drivers side and the REM and RCA wires are run down the passenger side. Whenever the car is running, even with the stereo volume turned down to 0 there will be a constant high pitched whine over the subs. The more you rev your engine the louder the noise will get. I am not sure where to begin to look to fix this problem. I also noticed when you turn on your heater the noise will increase dramatically. Can someone please help??