Ive had my D3 installed in 3 diff vehicles, a 06 Altima, 05 CTS and now its in my 04 Escalade. Yesterday i noticed when i put my key in and put it in the on position, im hearing a high pitched interference noise. I never noticed it until yesterday and ive had it installed for a year and a couple months. Any idea what it could be? I havent installed or done anything different lately.

figured it out. it was one of the two adjustable knobs on the gmos-04 adapter box that had to be turned down a little bit.