no trailer brake lights on 2005 Chevrolet Silverado 2500 HD

my 2005 silverado has no trailer brake lights. everything else works -signals,running ect. all of the truck works just not the trailer brake lights. fusses all good and I just replaced module in back end of truck - still no luck.

You need to get out your meter and find where you're losing power or ground. It's likely to be a faulty connection somewhere under the truck.
You may need to find an auto electric shop or consult a GM specialist for help.
If you want to find a specialist, here's a directory link for you: