Flow gates donnot open

there will be a air flow setting knob that controls whether air is defrost or on feet or from the console vents.

Your coil that allows air to pass through for A/C or heat could be plugged or the thermostat is sticking.

One of your gate valve is not opening. You might have a vacuum leak on the gate valve

Keep this principle in mind: Heat, flows INTO cold... When you hold an ice cube in your hand, your hand gets cold because the heat from your hand is flowing INTO the clod ice cube, NOT because the cold is flowing into your hand.

On this particular vehicle (like many modern vehicles), hot water from the engine flows through the heater core at all times, even when you have the A/C on or when you have nothing (A/C, heat or vent) on. The system uses a door that closes down over the air opening to the heater core to keep you from feeling warm/hot air when it is not desired. The reason(s) you feel that the vent air is warm even when the outside temperature is somewhat cool is/could be caused by the following:

First, although as mentioned above, the heater core is restricted from receiving air when you are not commanding heat by the control panel, the heater core ultimately ends up as warm as the engine temperature. This is generally somewhere around 200 degrees F. Because all the air coming out of your vent(s) must pass over the door that restricts air over the heater core, and because the heater core gets so hot, some of that heat is picked up by air passing over the hot door even though it is closed.

Second, the door that restricts airflow from passing over the heater core has a seal around it. After a period of time this rubber (or usually felt) seal deteriorates, allowing some air to actually pass over the heater core. Since the core is hot all the time, some of the air gets heat loaded, producing warmed air.

Third, the door is operated by (in the case of your vehicle) an electric motor which responds gradually/proportionately to the setting you select on the temperature dial. If the motor gets out of calibration (can happen from time to time), if the control head has a 'glitch' and sends an incorrect signal (chronically, usually), or if the electric motor (called an actuator and contains its own little electronic 'brain') becomes faulty, the door may not be closing completely. This symptom can also be caused by a problem with the door itself, where the door gets stuck due to warping of the plastic case, a foreign object preventing it from closing (usually a pen or toy dropped into a vent or defrost opening), or a broken or cracked door hinge.

Last, the vent intake opening, where the 'fresh' air comes into the car on the 'vent' setting, is located just below the windshield on the passenger side. This opening receives its air directly off of the sun-baked, engine-heated hood and because of this the air is never as cool as outside air even on a cooler night.

I hope this answers your question. Many domestic vehicle manufacturers have begun installing heater control valves on their vehicles once again as they nearly all used to have. Note that the fix for most everything I have mentioned here requires removal of the dash of the vehicle or replacement of the control head and therefore is in many cases not worth the investment if it is not an extreme problem (for example, unless the system is stuck on full heat in the middle of summer. Additionally, remember that, if you so desire, manual shutoff valves can be placed in the heater hose lines (please consult a qualified mechanic as water from a vehicle can and will scald and burn you!), allowing you to manually shut off the flow of water into the heater core, thus reducing some of the heat (Readers note that certain foreign vehicles REQUIRE water flow through the heater core at all times for engine cooling and are not candidates for this procedure!).


Parts Of BMW.

checks the air flow selector but it sure do not have vacuum in the control panel and it works with vacuum from the engine has a small hose that is used for vacuum and this controls the gate that directs air to the places diferntes ...

In the box that is mounted evaporator and heater is a gate that operates with vacuum and the temperature selector is opened and closed to pass the airepor the evaporator or the heater

Inside the ventilation system there is gates that open and close to direct the air flow. These are operated on vacuum on most vehicles. The hose for that perticular gate may have disconnected somehow or has a hole in it. I suggest you take the heater controls out and see if there is a plug with a series of colored hoses on it. it so you'll have to trace each of them to see which one is the problem. Now you may be able to get some help from you local dealers mechanic who just may know the color code for that gate. (which would be a bonus) Good Luck

I had a 90 Cutlass Supreme that did that too. I just got into the dash and forced the arm on the main gate open.

Its just a vent damper plate not operating, it's like a gate which controls the flow of air,,usually they are operated by vacuum, or cables.
Service center time, unless you are handy with your own repairs.

sound like heater box has issues. doies the heater box have trash in it, like leaves???? It might be a vacuum line dry rottering and making the dampher not work properally. I need to be there to really check it out??????