What's wrong with the van not blowing warm air

The main reasons why the vehicle heater is not hot are: 1, and the hot water does not reach the heater box. These include the blockage of heating pipes and the failure of warm water valves. This fault can be realized only by touching two warm water pipes in front of the warm water valve in the engine compartment. If one is hot and the other is cold, there is something wrong with the warm water or the warm water piping system. 2. Hot air will not be sent out from the air outlet. Among them, the air-conditioning filter element is blocked, the air-conditioning heater damper is stuck, the control cable falls off or the control motor fails. 3. The air volume of the blower is too small. For this kind of problem, it is necessary to disassemble and check whether the air conditioning filter element is dirty and blocked, and whether the blower is insufficient to supply air. If these problems are eliminated, but the fault still exists, there may be a problem with the damper control of the air conditioning duct.