Low coolant level, or a plugged heater core.
If the air conditioner in a Mitsubishi Legnum is not working, there could be a blown fuse. There could also be a loose cable, or a problem with the heater motor.
Could be a bad heater core...also, could be low coolant level. With my car, it was Heater matrix clogged with radiator sealant. The workshop cleaned it and it's start working fine!
Could this be 2 separate problems?Stuck in defrost modeNo heatSee "Related Questions" below for more about both
There are signs that there is a problem with a hot water heater. When you cannot get your water to heat. It could be signs that the pipes leading to the heater are leaking. It could be a problem with the thermostat in the heater.
Your heater coil is bad.
COULD BE A BAD HEATER CORE COULD BE A BAD HEATER CORE sounds like the heater control switch needs replacing.if that doesnt fix it, you need new heater core
If the seat warmer on a 2004 Saturn Vue is not working it could be a problem with the heater element. This element can be found under the seat and will be easier to access from the rear of the seat.
A vacuum leak, or one of the doors is sticking/bad vacuum motor in the heater box.
If you are absolutely, positively sure that your coolant level is not low......then your heater core could be plugged. Or the control that turns the coolant flow on/off to the heater isn't working. Make sure the control is working, the flush the radiator. Should cure the problem.
Assuming the blower fan is working but it blows cold air, it could be,Faulty temp blend door actuator.Plugged up heater core.Faulty thermostat,Low coolant level,
If you have lost a sufficient amount of coolant this will stop the heater working because there will be no hot water in the heater rad.