01 tahoe ls stereo noise

[60ratrod]

so i have a noise coming from my stereo, mostly the front passenger door speakers, that fluctuates with my rpms. i turn the stereo off and the noise goes away. sometimes if i shut off the stereo before i shut my tahoe off and turn it on after i start my tahoe the noise will go away for a while. the stereo is a pioneer aftermarket unit that you can get from walmart for $100. and my tahoe is equipped with a factory sub and amp. i ended up cutting the factory harness connector off and installed the stereo with a print off of the stereo wiring diagrams. is it possible the speed wire for auto volume leveling with the factory radio is causing interferance? or could i be getting feedback from somewhere else?? could the amp be going bad??

[droppedgmc]

sounds like a grounding problem. have you tried reversing the wires you hooked up to it?

[71Sixer]

This is a grounding problem as droppedgmc said, but I wouldn't think the wires are reversed. This happens a lot with aftermarket units because you inadvertently create a ground loop as your grounding location for the new head unit is different from the speakers. This is because the chassis resistance back to - or ground is different depending on where is located. Electronics are sensitive to this. The difference in potential here causes electrical noise which is heard through the speakers. The easiest way to solve this is by grounding them all in the same location.

[60ratrod]

ok. well when i hooked it up the front speakers only worked if i hooked up one of the speaker wires, but i wouldn't have sound if i hooked up both so i only hooked up one and i have sound out of both. so i guess i'll pull the head and switch the wires. but on a side note i cut the wires flush and put some heat shrink on the ends of the wires i didn't need so they weren't grounding out. i'll let you guys know how it works out

[71Sixer]

From the sound of it I would definitely try to dig up a wiring diagram to see where the wires go to. You should have a positive and negative to each speaker. Double check your polarity from the head unit to any amplifiers and so on. This is a great website if you want some more info on car audio: http://www.bcae1.com/

[60ratrod]

well i think that i got it now. and with the schematic that i had printed off i had the wires matched to where they were supposed to go and didn't have any sound coming out, and i even tried swapping the wires around and still found no sound. but now the speakers sound a lot better. i'll just have to keep my ear open to see if the issue comes back, which i don't think that it will. but i shouldn't have been a tard and cut the factory plug off

[60ratrod]

ok so i didn't fix the noise. so i called my dad who has been a gm tech for 27 years, and asked him what it could be. he told me that it is more than likely the radio ground itself, since i used the ground wire that is in the factory harness. but before i do anymore cutting, splicing, and wire routing/replacing to try unhooking the alternator. so i tried that and the whine went away. so now what i am going to attempt is to run a different ground to the steering collumn as my dad suggested since it grounds to the chasis. i'll keep you guys posted on what happens

[71Sixer]

Are you using RCA cables to your amplifier, if so do they have a good shield? Also, you may look into using a ground loop isolator between your new head unit and the amp if you get your grounds hooked up properly and you still have a problem.

[60ratrod]

at this point everything in the system, except the head unit, is all factory. including the amp. from what my dad told me, the factory stereo harness ground wire is a poor choice for aftermarket head units since there are many items that ground with that. i just gotta pull the dash bezzel and attempt to run a new ground and see how that works