I've installed headrest DVD monitors in a 2002 Chevrolet suburban with audio through an Fm modulator. I'm getting a ground loop on the audio side, not visible on the video side.
The 12V+ is through the Audio 2 circuit in the fuse block.
Any suggestion on a ground point under the dash or in the center console?
I've tried grounding the framing for the dash itself and to a bolt holding the drivers side seat down. And am still getting alternator whine.

Thanks in advance,

Derek

 

what type ofheadrests did you buy? how much money?.....cheap units will give you nothing but problems.
Your ground should be into the body of the vehicle using a self tapping screw, with the paint scratched off. If that doesn't fix it, look for a pinched wire, or try another fm modulator