yea, check your vacuum lines, i believe its the red shaded clear line that runs on the passenger side of your truck, . by the heater blower motor, also top off your radiator, is the blower coming on>? email me at eliteprofessionals@live.com
heater core plugged or air locked check to see if hoses going to heater core are hot
thermostat probably stuck open needs to be checked or replaced
The heater core is usually your last resort. So now start from the end to the beginning, core, thermostat, flush, hose, fluids. Follow the trail and your bound to find your answer.
Try flushing heater core Try flushing heater core
You may need to replace your Thermostat or your Heater Core.
Could be a bad thermostat or heater core
How did you change the thermostat?
You need to change your thermostat in the car.
Your thermostat is stuck open.
If it is leaking coolant. And you changed the thermostat. I would then move to this section. Flush the radiator and the heater core. This can be done at a certified shop with a reliable mechanic.
You should check the thermostat and the fuse for the heater.
One reason your home electric heater is blowing cold air is the heating elements are burned out. A bad thermostat may also be the problem.