heating problem on 2000 Mercury Mountaineer

i have no heat in the truck could it be the thermostat in the past the trucks i had thats what it was but i do not know to much about this one 2000 mercury mountaineer V8

1 answer
If the engine is not getting up to operating temperature, or it is taking a long time, then I would replace the thermostat.
If the engine temperature is fine, then you may have another issue with the climate system or the heater core.