The regulator sure doesn't go there, the CC-M has ditch light outputs on pins 7-8 and 9-10, and they're LED outputs.
The 5V regulator wired to the DCDS isn't needed with the CC-M. I believe that was supplying the opto isolators of the DCDS, it's not needed in this installation. I think you'll find the regulator is feeding the DCDS, and none is required for the ERR installation.