Advice needed: Audio + whine from my GPS

[TonyT607]

For any elecrtical gurus out there:

I have a Garmin Quest GPS, XM Roady, and V1 mounted on the bike (new ST).

To consolidate the audio to my Etymotic ER-6i's I have a little black box from Accessory Workshop (now defunct). The little box has one stereo input (XM), one mono input (GPS or V1) and a single output plug. Since I can only run two inputs I normally have the V1 and XM plugged in, and don't rely on the GPS audio prompting. I took a short ride today and thought I would test the Garmin audio. Well, I plugged it in and got a high pitched whine, which lessened a bit when I pulled the brake lever...( ? ) It didn't stop at all, and did not change volume or pitch with the engine RPM's.

The GPS is mounted with the factory Garmin M/C mount (which supplies power and an audio jack). The power cables are hard wired directly to the battery (via a custom wiring harness from Eastern Beaver). The harness also supplies leads for my other gadgets. The audio from the XM and V1 is crystal clear.

Obviously I'm getting some kind of interference but that's where my electrical knowledge ends.......and why would the whine die down when the brake is activated ? Can I install some kind of filter ?

Thanks !

[BobFV1]

Methinks you need a ground loop isolator. There are many out on the market - here is one:

http://www.cellset.com/AuxSwitchSet2.html

I put one on my bike - I run a Roady 2 and Garmin 2610 through an AutoCom, and it cleared up the buzz which initially made my Garmin audio inaudible.

[TonyT607]

Thanks Bob - I think that's the ticket. I'll look into it.

Good luck with the GS, let me know if I can help with any support from NJ.