Dirty Power

Ok I have checked all RCAs with a Q BOX and I have ran just RCAs to the amps and bypassing the X-Over and I still get a high pitched weeze sound.  I have checked all grounds and I am seeing 0 at all gounds for resistance on amps and x-over.  I checked the gound I used to ground the body and I am seeing .1 for resistance.  I re-ran my power and that did not help.  I also can hear the fans when the kick on throung the speakers.  I am thinking I have dirty power and if that is the case how do I take care of that?  I don't know what else to check.  The radio is also seeing 0 for resistance.  Any help would be great.

Thanks

use a ground loop isolator, how old is the car? does it have a noise suppressor?

Or does it happen when the car is switched off as well?

It sounds great when the car is off?  It is a 2003 SRT-4.

Sounds like engine-created noise.  This is caused by many things, most of them having to do with bad grounds.  However it seems you have made the proper measurements and your audio system grounds are OK, so now we begin with the harder to find stuff.

Start with your speaker wires.  I have seen a single loose strand in one speaker wire touch ground and cause the problem you describe.  Start at your amps and go hand-over-hand looking for damage or loose strands in all speaker wires.  Don't forget the wiring harness for the HU.  Next, it could be a bad or corroded engine ground strap.  Clean your battery terminals and battery connectors with a wire brush and baking soda/water.  Locate the engine ground strap and make sure it is intact, has a good connection to the chassis and is not corroded.  In some new cars, especially Chryslers and Fords, the engine ground strap is not made properly and the bolt is actually painted.  You want to remove all paint from this bolt and the connection point.  Next, and this is the tough one, it could be in your engine's ignition system.  A bad spark plug, spark plug wire, coil, distributor cap, coil wire, electronic ignition module, fuel injection computer, etc. etc. etc. can cause noise to be picked up in an after market saudio system.  This can be very difficult to track down and eliminate and can be very expensive to fix.  Dodge Neons (and PT Cruisers which are the exact same vehicles under the skin) are notorious for bad engine grounds and/or bad grounds in teh ECU (engine control unit.)  You may need to take the car to a shop with a computer analyzer and code reader for Chryslers to troubleshoot this one.

Best of luck.

If you have passive crossovers running off of this amp, move them out of the position where they are currently as well. What is the balance of the system comprised of?