Maniak is correct...you have CAN bus issues. You would be better off getting a radio from a 2003-2004 vehicle that is not CAN bus...such as a Mustang or Explorer. You want to look for one that snaps in...not bolts in. Although that could possibly be worked around...but not easily. 6 disk units up to 2003 (depending on vehicle) had a CD button on the lower left and usually took World Plugs. In 2004, that became a SAT button (the radio is satellite ready) and Ford switched to Phase II plugs. An adapter can be built to adapt to different plugs if you have the patience. None exist that I know of...I've had to build my own. But do some looking on ebay. There are a ton of Ford radios that will work. Do your homework.
But if you have the JBL system in your 1995, all bets are off. Your radio is actually back by your subwoofer and your dash unit is nothing more than a control unit.