Turn signals/flashers quit on 01 2500

From : sodakid2

Q: my turn signals and flashers quit working last night on my 01 dodge cummins as i was pulling my trailer. the flasher unit sounds like it is running all the time except when you turn on the signals or flashers.....and the turn signals make a hissing noise when you move the lever but no lights or signal lights in the dash come on. dealer wants close to $40 for a flasher relay but wont diagnose the problem without an appointment and is booked up till monday. any help would be appreciated. thanks! -- later........ eldon spokane wa 509 921-6635 .