DC is for Direct Current DC LO flashing is low 12 volt, (often bad or low batteries), DC HI flashing is high 12 volt supply (I do not know most common reason). I have not heard of DC re unless you are just saying DC and the re is :subject to or short for refer,. E-mail me at
Gatogonow@aol.com and I will e-mail a copy of the service manuals for the Norcold 1200 to you.