CobaltBob

I have a 2006 chevrolet cobalt ss supercharged and i recently bought the Dual xdvd8181 monitor. i first had to buy a 130 dollar wire harness because of the onstar and chimes in my car. i have evertyhing hooked up, but when i hook the ignition wire up, my guages dont work and neither does the digital mileage or temperature display. Also, when i hook the ignition wire up. the unit turns on and operates but there is no sound coming out of the speakers.Please help with suggestions, ive heard alot about problems with hooking these up in cobalts. wondering if you could help.