I have a 2007 Saturn Ion3 and I've been working on this issue for the better part of a year now. I've been doing car audio for a couple of decades now and I'll say that the basics have been covered a number of times already: signal is run on the opposite side of the car from the power; common ground point originating from the battery (located in the trunk); rerouted factory power cable running from the battery in the trunk to the alternator (the factory one ran diagonal from the rear right to the front left of the interior then out the firewall and back across the front of the engine to the alternator; now it runs straight down the passenger side); changed RCA cables out; and insured clean secure grounds. None of these basic tactics worked.
I've gone a few steps further even and changed the headunit from the Pioneer DEH-P500UB that I started off with to a Clarion DXZ665MP and then to a Pioneer DEH-P860MP with no change. I've run RCA cables all through the car but anytime I get near the area where the head unit sits, the noise is present. I've even grounded the shielding of the RCAs but that made it worse. I've used muting plugs and there is no noise with those in place. Tonight, I put in a top-of-the-line Alpine just to test but there was no difference. The noise seems to radiate from the dash and I'm not sure what to do at this point.
I'm wondering what else I should look at. Last September (2007), I took the alternator off and took it to a shop to have it examined, explaining my problem along the way. A day later, the shop advised that they couldnt find any problemls with the alt. I'd buy one anyway but that's $80+ spent on something that I don't know if it will solve the problem. Can a battery induce noise? Last winter, the battery would die over night. My local OReilly's checked the battery with one of their handheld scanners and told me it was fine but it still drains if the car is parked for longer than a few days. Of course, during the past 4 days now, the car has been in my garage stripped down completely with nothing connected to the battery at all and the batt still showed 12v on my DMM. So, I dont know if its really an issue.
Does anyone have any suggestions??? Thanks in advance!!
