Im looking for a reset code for my used Mazda3 2004. we took out the radio unit to fix the cd player, and when we put it back in, it has no power at all, no light, no message, just a blank screen. Can some one help me?

 

Where are you located? At least in the US there are no reset codes for the HU, just plug and play.

What exactly did you do to fix the CD player? I'd retrace whatever you disassembled and make sure everything got reconnected. I can't rememember if there is one, but if there's a fuse on the HU itself then check it. also check the fuse in the PJB.