No power to stereo or flip down monitor

[uk tahoe]

hi all , just done a dod delete on my 2007 tahoe , fitted a new battery aswell , turned truck on and nothing from stereo or flip down monitor no power at all to either of them , checked the stereo and amp fuses and there fine , really got me stumped as every thing else useing the same accessory power and key power is working fine .

Any help be much appreciated