Sounds like you have a couple issues. Whine is 50% battery power issue and 50% antenna lead issue. To check where yours is coming from make sure the radio case has a good ground. Then take a wire attached to ground and just touch the center connector for the antenna. Whine goes away? = Antenna cable shielding is junk.
To see if it's alternator is simple, connect a wire directly from the battery to the power feed on the unit. If the whine goes away or is greatly reduced it's from the alternator. You can get filters for the power feed at most stereo/electronics shops to eliminate it.
You might have sound unless the alternator feedback is killing the signal.
Do you hear anything if you turn the key to on but no engine running?
If not you have some mixed up wiring or the new head unit blew the inputs in the factory amp with a high signal levels.
What make/model of head unit? I'll see if I can find it's wiring diagram online and what you need to connect to the truck.
Wednesday, September 13th, 2017 AT 8:18 PM