I am installing a Zumo 660 and NIM module. Nim works well. I have a ground loop that is cutting the left channel out when the Zumo is Power/Grounded to the bike. If I disable power and run on battery, all is well. Other devices DroidX, Ipod play through the Auxillary just fine. Car cradle shows the same problem on the bike.
I installed a RadioShack gound loop isolator, but found that the volume is cut quite a bit. Are there better GLI's that others have used that doesn't reduce volume?

Thanks,

2011 RG Ultra

 

What wires did you tap into for power and ground ...

 

I started with pwr and ground from air temp gage. I also tried grnd from bl/gr on audio harness. Schematic in manual shows that as grounding on rear ground point. Where as guages are grounded on front and using the frame to get to the battery. I ordered a cruchfield isolator in hopes that it might be better quality than radioshack.

I haven't stretched a ground directly to the battery. It didn't seem like the pwr locationmattered. It fails with only the ground connected.

 

Did you try running a temporary ground wire from the device to a better ground? If that works, maybe a corroded or undersized ground wire exists. With power isolated, take a resistance reading from the ground terminal in question to the negative ground wire and see how much resistance is there. A ground loop to me is a difference in potential from another ground. Those devices you added dont seem like big amp draws, very interesting problem that seems to show electrical systems are still a weak spot with motorcycles in general.

 

I didn't have any luck with grounding locations. The ground loop isolator I ordered from Crutchfield worked well. With no detectable loss of volume.