2nd Gen Non-Engine/Transmission Electrical noise through sound system?

[SSage]

Recently some thing has started causing a whining noise in my sound system. I haven't added anything new. I only get the noise when the key is in the start or position or when the truck is running. Sometimes it goes away for a spell but I'm getting the loud whining about 90% of the time now.



My battery grounds are tight, the noise is constant with the key in the start position. The noise stays when the engine is running. When the key switch is in the ACC position the noise goes away and the speakers are totally clean with no whine. Dash lights are all good, ham radio is not affected. I unplugged the phone charger etc. . No change. Sound system grounds seem good, the music is fine once you drown out the noise... .



Any ideas? Truck is running fine. Noise started last month, about two months ago I changed the fuel relay on the fire wall. I traced out my speaker wires to the amps, don't see any damage. Power leads are good.





I'm stumped. . #@$%!

 

[jhoughton]

Sounds like a motor running. Try turning off the heater/ac fan and see if it is still there. Heater blower does not run in ACC position.

 

[SSage]

I went out and started removing cables trying to find the source and I think its the head units front channel.



After looking under the hood and checking grounds again I pulled the front RCA patch cables to my amp and the noise stopped. Swapped the rear patch cables to the front and the sucker is clear, pulled those and moved the front cables to the rear speakers and the whine moves back. So, my front right channel source is the main source of the noise, the left front noise is less. The fader has no effect on the sound but the rear patch cables are clean and clear.



So, I guess my pioneer head unit's front channel is toast. I doubt my huge deavy duty monster brand patch cables are bad. I know its not the amps, I think I need a new head unit or I could bridge the 4 channel amp and run just my front speakers. Don't know if its a good idea to only run the amp on two out of four channels... . It really sucks since I like my double din pioneer.

 

[fest3er]

Ah, wait; a little more spelunking is in order. You're hearink a noise in the right front. Did you move the the head-end of the patch or the amp-end? Or worded differently, does the noise follow the cord or does it follow the channel? If I read correctly, you swapped the RCA connectors at the amp. So you only know right now that something between the head and the amp is bad, including the monster cable. Can you swap the cables at the head end? That will tell you for sure whether it's the cable or the head.

 

[SSage]

Ah, wait; a little more spelunking is in order. You're hearink a noise in the right front. Did you move the the head-end of the patch or the amp-end? Or worded differently, does the noise follow the cord or does it follow the channel? If I read correctly, you swapped the RCA connectors at the amp. So you only know right now that something between the head and the amp is bad, including the monster cable. Can you swap the cables at the head end? That will tell you for sure whether it's the cable or the head.

Yep, I'm going to check the head end of the cables in the morning. I ran out of steam and didn't feel like pulling the head unit out. At least it's not some grounding gremlin, the head unit is about 4 years old... . kinda short lived compared to my last one. I doubt its the patch cable, I'll find out tomorrow.