Engine feedback

Have submitted ticket Re: 14741 and replied to the questions but email has bounced back as non deliverable.

Purchased blue tooth receiver BR-C1-B. Installed in my car but there is a feedback whistle from the engine. Any way of eliminating this?

If you plug in another device and play audio through the aux port does it do it or is it only when this is plugged in? Have you tried placing it in different locations in the car?