Injectors not firing- car wont start

Question

wired in sony stereo/cd player in as per instructions provided by shop that sold me the unit . instructions were wrong . they mixed up the constant feed and the ign feeds .
Now i have NO constant power feed anywhere . and injectors wont fire. have checked fuel pump and plugs and both working fine.
Feel its blown a fuse somewhere but i cant find where .
any ideas on where to look ?
have checked all std under dsah fuses and the 2 under hood boxes