Well, the simple thing is to first check for water in the res, then check to make sure the pump is running by listening to it while someone else pushes/pulls the washer switch. If no sound, then the pump wire is disconnected or the fuse is blown. If the pump makes a "whrrrrrzzzz" sound and no water, then there is a hose disconnected between the res and the washer jets OR there is a kink in it somehwere OR the jets themselves are clogged (maybe with window installation debris??)... they can be cleaned with a fine needle or piece of fine wire pushing in and out of them while someone pulls the washer switch. If you have access to compressesd air, they can also be blown out by disconnecting the hose at the res, then pushing a rubber tip nozzle inot the hose and blow in no more then 60psi.
Hope this helps.
It would also help others help you if you were to list your truck year/details/mods on your signature. Go to the User Control Panel under the Discusion Forums tab at the top of any TDR page and use "edit signature".