If you're talking about the one on the frame rail on the driver's side, there's a small black plastic lever which opened up the drain.
The sensor in the fuel filter housing is bad. I had the same problem on my 2003 6.0L F-350. I had the Ford dealership change the sensor ($110.00) and I have not had the light come since.
Yes, it is on top of the engine, behind & under the plastic trim piece. There is a small plastic RED nob to turn to let the water out. Good Luck!
It is located on the driver's side frame rail underneath the driver's door
On the lower rear end or side of oil pan
Locate the HFCM module under the truck and just in front of the firewall on the driver's side. There is a hex key plug which you need to remove to drain the water. Allow to drain for about 10-15 seconds. Some people recommend you regularly do this once every 1-2 months to avoid the warning light.
under truck, front drivers door, inside of truck frame is fuel filter, on side of fuel filter is a bolt keyed to a hex head, turn that bolt then let water and fuel drain for 10 to 15 seconds then tighten back up.
It's down under the truck. Along side the frame.
Ford never made a 350 motor
Drain the water from the cooling system. Remove the radiator hose from the thermostat housing. Remove the thermostat housing retaining bolts. Reverse the process to install the new thermostat.
Behind the radiator cooling fan.
You poor water onto the console.
under the carborator