something is still not connected properly. if you are familiar with a multi-meter/voltmeter, test all your power connections (memory, acc+, and ground). you stated that you grounded the deck seperately from the factory harness. in that case, make sure you grounded it to a solid part of your chassis and not to a metal dash bracket. reason being is because dash brackets are tack-welded into place, therefore resulting in a poor grounding plane. also use a wire brush with your drill and scrape all dirt/paint from your grounding point, and make sure you use a locking washer with your screw to assure that the ground is not loose.

if you are still stumped...take it to a perfessional.