Detonate

I replaced a previous aftermarket head unit on a W210 that had a constant static hum when the head unit was on. The new head unit doesn't have the hum or static but it does has a popping or thump sound when changing sources, when volume moves between 0 and 1, and when it's turned on and off.

I purchased the head unit at Crutchfield. They told me it's a grounding issue and that I should ground the head unit directly to the car rather than through the wiring harness.

Does any body know a good ground spot in a W210 near the head unit?
What gauge wire should I use?

James Sullo

If you remove the window switch panel surrounding the shifter and the ash tray assembly, you will gain access to the floor panel. Look for an existing bolt or screw (maybe holding the shifter to the floor) or you could remove the panel under the steering column and look for a metal support. Then run a ground wire from one or the other to the head unit. I recently replaced the HU on my W210 wagon and had no problems using the factory harness/ground. However, I had a problem with my corvette last year with popping and engine noise after installing a new HU. I ran a dedicated ground from the engine compartment and made a grounding block inside the cabin and then directly to the head unit and that solved the problem. I hope this helps.