NOTE: For aftermarket units, bolt ground wire directly to frame of car instead of using chassis ground wire on harness. Using the harness ground almost always introduces alternator whine.
I am about to install a Kenwood KDC-X592 ,and after reading this I was wondering, as this is my first head unit install, where is the easiest place to bolt the ground wire directly to the frame?
I am going to have to argue with that.
I have installed no less a 100 head units and have never had an instance where installing a separate ground for the head unit stopped alternator noise.
Whenever I have run into alternator noise its been a rather consistant batch of issues:
1. RCAs or high level input wiring are running next to amplifier power wires.
2. Bad equipment, seen this in head units, amps, and EQs, just swapping the unit with another of the same model solved the problem.
3. Caroded power wire connections. I only saw this once but the amp was getting only 9 volts, once investigated, from the battery to the amp side of th epower wire fuse was dropping 5 volts for rusted out connections. Replaced these and all was well.
4. Connecting an aftermarket headunit into a car with an older Bose system that simply can not handle the input levels from the new headunits speaker outputs or RCA outputs.
In the several instances where I had alternator noise, a seperate headunit ground never solved it. Not to say it can't. It just was never my probem.
