Check your coolant level. If its too low the sensor won't read the temperature of your coolant.
if the heater does not blow out warm air change the setting.
It could be the thermostat on the engine. If the engine does not warm up adequately the heater will never blow hot air.
heater on at idle and will not blow warm air. when moving it blows the warm air from the vents. what will cause this
Isn't a heater supposed to blow warm air?
engine not warm, low coolant, or stuck thermostat
Faulty thermostat. Plugged heater core. Temp blend door malfunction.
Yes.
Low on coolant. Stuck open thermostat. Poor circulation (plugged heater core).
Any heater that only blows luke warm air isn't getting warm or hot water to the coil. This sounds like a problem with the thermostat not closing, and allowing the engine to heat the water properly for the heater.
Heater core may be plugged . Flush the cooling system, also check thermostat.
The heater core is blocked, or a heater hose has collapsed, keeping hot engine coolant from getting to the core. The "blend air" door may be stuck in the open position, keeping warm air from circulating, and dumping in cold outside air. I am assuming that engine coolant and water pump is good.
Probably need to add antifreeze. Check the Radiator not the overflow tank. If you are low on antifreeze it will not circulate through the heater core.