Heater does not work, doors open ok but no heat

HVAC, the heater is not working?
the resistor only makes fan work , on low speeds.
1: is the fan blowing? heard and felt? on HIGH?
2: is engine coolant at 180F temp, or more holding, IT must, or there will not be heat,.
3: are both fire wall heater core hoses hot, fully? if one is cold the core is blocked. (flush it out)
4: Ok, we have hot water coolant to core (heater core) so is the damper open?, yes, then now you have heat for sure.

if all that is greek , get car serviced.
or buy the FSM book read , HVAC chapter
the factory service manual

probably heater door that allows heat into the interior not working or whatever controls you have that opens this door defective...1st make sure ur getting heat into your heater core by feeling both hoses which should both be hot, if one not hot then perhaps the valve that opens the water flow through the heater is not opening...sometimes u can see this visibly whereas you can then try to manually open it...

Air Temperature Control Blend Door Failure No Heat or no AC (dependes on where door sticks)

In all modern cars there is a tiny DC electric motor driven gear drive that moves a plastic door that blends heated and cooled air from the AC and the heater core, this is called (interestedly enough) the air temperature control blend door actuator. The motor that moves this door fails because the door starts sticking from warping, most common complaint is no heat but it can be no AC as well. To replace these parts (blend door and blend door actuator) you must remove the entire dash from the car. Always have this problem confirmed by a dealer or qualified repair shop as it is a very expensive repair.

Other causes of no heat in the cabin are engine thermostats that are stuck open (engine runs cold) or air bubbles in the cooling system.

Assuming the car does not overheat (Ruling out the water pump), I would look for something not opening the heater door. I think this car uses a pneumatic system to open the door for the fan to blow air over the heater core. If that door does not open, you won't get any heat. You probably have a cracked or broken pnuematic line behind the dash that controls the door.

Sounds like the blend door or blend motor is not functioning/opening. This door allows the heat/cold air to come in by adjusting open, closed or anywhere in-between for temp. Start there. They are usually vacuum controlled and mounted under the front dashboard near the knee board.

are heater hoses hot there is a valve in the heater hose check to see if it is open if thats ok the door that controls the heat is not working located on top of the heater box usually not to easy to get to

blower motor working?..do you have vacuum control traps doors from defrost to cabin heat..may have bad vacumm line or thermostat may be stuck open or heater control valve bad.if fogging winodws the heater core is bad.

Check the motor on the top of the heater plenum. It turns a shaft to shift the blender door which controls the input to this plenum either the heater core or the evaporator core (ac). You may find the motor is OK but the shaft (plastic) has broken and the blender door has to be replaced. This is a costly job that involves removing this plenum after removing the dash. A shortcut I found online was to cut a hole under the blender door and replace it through this opening. After replacing you can seal up the hole with epoxy. I cut three sides of a square hole leaving the back uncut. Pull down and the blender door can be removed. My problem was on a 1997 Explorer.

There is a valve on one of the heater hoses that allows heated water to flow through the heater core when you select heat. With heat selected and car warmed up check to see if both of the hoses feel warm. If not then water is not flowing through heater core and valve may need replaced or heater core is stopped up.

Where the rubber hose goes into the heater, there should be an air switch that opens an closes a shut off to the heater coil try it manual it should open an close by hand