I just changed out the stock deck for an aftermarket dck and now my power door locks wont work or my anti-theft device. Any ideas why?

 

Have you checked the fuses?
Did you disconnect the battery before you installed the stereo?
Did you cut the harness or use an adapter?
Do the power door locks work if you use the switch on the driver's door?

 

Your theft system could be tied into your door locks depending on what kind of system it is, and it could be tripped by installing the new deck. Hopefully you used a harness. Disconnect the battery install the old one and see what happens.

 

i did this on my 04 civic sedan with no issues. When i did it on my 98 i had the same problem. i had to make a jumper from one wire to another to make it work.