Code P0116 2003 Ram 2500

From : clark

Q: i have a haynes manual and am wanting to change the thermostat. to do that the manual says i must first drain the coolant. to drain the coolant the manual says 1. with the engine running move the heater control to maximum heat. 2. place a large container under the radiator to catch the coolant mixture as its drained. 3. without removing the radiator pressure cap and with the system *not* under pressure shut off the engine and open the drain cock see illustration. 4. the coolant resevoir tank should empty first then remove the radiator pressure cap. .... etc... the problem im having is at step 4. after following the first three steps and opening the drain cock the illustration calls it drain fitting nothing comes out. wahhh! can anyone tell me whats missing in these steps that i need to be sure to do for this to work thanks. mark .