2001 Chevy Silverado, intermittent ringing from aftermarket stereo, not alternator whine or ground.

BG710 · July 3, 2020

I have a 2001 Chevrolet Silverado 4x4 extended cab, love the truck and give it everything it needs, do most of the maintenance on it myself. Recently installed an aftermarket radio as well as a subwoofer. The unit is a Kenwood KDC-X304. The unit produces good sound, but I have had one issue. I installed everything myself to make sure the job was done right.

Whether the vehicle is on or off, there is an intermittent ringing that comes through the speakers, mainly noticable at higher volumes. The ringing starts and stops. It may ring for 10 seconds, then stop for 10 seconds, then resume. It's not tied at all to the alternator/engine speed.

Troubleshooting steps I've taken:

1) Cutting and recrimping the stereo ground wire.

2) Removed, sanded, and cleaned the factory ground points.

3) Disconnected sub to isolate it as a potential issue, ringing was still present.

I'm at a loss as to what I should do next. It seems like electrical noise of some kind coming from one of the truck's systems, but I'm unable to determine what. Like I said, It happens regardless of if the truck is on or off, and always comes and goes.

If anybody has advice I'd welcome it.

BG710 · July 15, 2020

I still haven't been able to track this down. I have tried a few additional things.

1) Used Deoxit D5 contact cleaner on all accessible electrical connections.

2) When installing my sub and running the power wire, I replaced the positive contact with a gold plated brass one with an end compatible with wires. To troubleshoot, I have now replaced the negative contact with an identical one and gave both a light coating of 3M silicone paste. No change.

I just have no clue what's causing this. Like I said, the music will go from sounding crystal clear to just having this ringing in the background for maybe 5-15 seconds then it's back to crystal clear. Happens when the engine is off too.

It must be some type of electrical noise, but I don't know the first thing about tracking it down. I suppose it's even possible the head unit could be the problem, though I hope that's not the case.

dsr611 · July 15, 2020

Where did you run the power wires for the amp and the RCAs from head unit to amp? It's been a long while since I've been into car audio, but, you can get electrical interference between the + wiring and RCA cables if they are ran next to each other. We would always run one down the driver side and the other down the passenger side.

BG710 · July 15, 2020

46 minutes ago, dsr611 said:

Where did you run the power wires for the amp and the RCAs from head unit to amp? It's been a long while since I've been into car audio, but, you can get electrical interference between the + wiring and RCA cables if they are ran next to each other. We would always run one down the driver side and the other down the passenger side.

I was sure to route the RCAs and remote turn on wire on one side, and the subwoofer volume control and power wire on the other side.

The sound persists when the sub (which is a powered sub) is fully disconnected as well.