popping sound

i put a panasonic in dash dvd/screen and hideaway unit into a 2004 chev silverado duramax diesel. i used a gmos-3 interface unit in order to maintain the use of the onstar and factory bose speakers. The system worked great for the longest time, but now he is getting a popping sound through his speakers when he applies the brake. I tried different grounds, different power source, different rcas, ground loop isolators, but no luck yet. any ideas out there?

You could try installing a polarized capacitor of around 1,000 micro farad across the orange and white wires of the brake switch. You may also have to install one from ground to each of the wires as well. Try the first example and see if it helps. If the vehicle has other switch pops or noise (wipers, power windows, signals) it more likely means that you have a poor ground on your audio system somewhere. Is there anything wired into the brake circuit like a brake booster? Itmay be the cause.sparky