water leaking through roof of cab. 379 ( 2003 ).

You may still have warranty on the truck if its a 2017.
Leaking from the roof or just the floor getting wet?
Some of the new trucks have had leaking seals between the sleeper and the cab. If it has the vents on the back of the sleeper those can leak too. Sometimes holes in the sleeper floor do not get covered properly. Improperly adjusted sleeper doors can cause that as well. Also could just be the A/C drain plugged on the passenger firewall. Besides that, air horns, clearance lights, windshields, spot lights, aftermarket antennas, ect. Get a helper sitting inside the cab. Spray it all down with a water hose and see where it comes in.

 

Mine is leaking in around wiper shaft that wiper arm goes on it's coming in around the firewall coming in around the fresh air vent coming in around the service panel it's just been one big leak since day one I was just wondering if anybody else was experiencing the same thing.

 

I am currently into horn removal and capping horn holes
I can see where the water has been coming into roof from horns