Put it this way if the orange wire did come loose and ground out, it would've blown the fuse. BUT if your SURE the fuse for the tail and dash lights is good, then only pull the radio out to use the orange wire to supply a fused(5-7.5amp) power source to it to see if the lights come on. and if they do without blowing that fuse then the problem is the dimmer switch. Also if you swear to it that the tail/dash lights fuse is NOT BLOWN then pull out the dimmer switch (use a butter knife or dull flat head screw driver to prevent scratchs) and give it a good tap or smack with your hand or very aggresivly move the plug aroung to try and see if there is a problem with the connection
i know first hand when i got my EG8 the dimmer was bad and i had to smack the dash right by the dimmer switch to get it working finally so then I replaced the switch

cliff notes:
try new dimmer switch
put power to orange wire behind radio to see lights come on