Secondary ac temperature control door shaft broke

It is most likely that you have a sticking air temperature or blend door that is warped and or the electric actuator motor is defective. When the door warps it usually ruins the little drive motor gearbox.

are you talking room ac or vehicle ac
the room thermostat is adjusted by the remote control and is fixed to high and low parameters and cannot be altered
Hugh fluctuations in temperature can be from people leaving the door open for too long or not closing all the windows and doors
for a car ac it is preset

Sounds like your blend door broke.
Go to YOUTUBE and look up your cars (model and year) blend door, for possible help in locating the door, sometimes it's easy to get to and move the door manually.

Hi there:
Error Code 24 - AC/Heater Air Temperature Control Blend Door failure
If it comes up 24 or 25 it is the blend door actuaton, or the shaft on the door is stuck (rust). Basically, there's a small geared electic motor that controls the blend door position of the hot/cold blend of air; keep in mind that this device is called an actuator and it breaks.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

The thermostat cannot cause your heater to go out, though the heater will run a little cooler if the thermostat is stuck open. Please see my tip at http://www.fixya.com/cars/r6235876-no_heat_fan_blowing_cold_air to troubleshoot the heater. In particular, I would start by checking the temperature control cable adjustments. I have pasted instructions from autozone.com below.

If you really want to change the thermostat, please see my tip at http://www.fixya.com/cars/r5929960-s_thermostat . The thermostat is in the housing at the end of the upper radiator hose.

For the speedo, It's probably a broken cable. Have someone take the cable off the tranny and spin the cable in their fingers while you watch the speedo. If the speedo works, the problem is with the gear in the tranny, else the cable is broke.

Let me know if you have more questions along your journey. :o)



Heater temperature control cables to blend door and heater water valve--adjustment:
WATER VALVE CONTROL ROD

See Figure 8
When adjusting the water valve control rod, disconnect the temperature control cable at the air mix door lever and then adjust air mix door control cable. Next, adjust the control rod. Reconnect the temperature control cable and then readjust it.

1. Push the air mix door lever in the correct direction.
2. Pull the control rod in the direction shown (in the accompanying illustration) until there is an 0.08 in. (2mm) clearance between the ends of the rod and link lever. Connect the rod to the door lever.

TEMPERATURE CONTROL CABLE
See Figure 9
Move the temperature control lever to the cold position. Push the cable sheathing and the air mix door lever in the correct and then tighten the clamp. Verify proper operation.

Try locating the heater hoses. Start with the vehicle cool and turn it on and wait till the engine temperature reaches the correct temperature. This should send fluid through the heater hoses. Feel the heater hoses for a change in temperature. If there is no change in heat after a while the problem is in your thermostat. If one heater hose is hot while the other is not than the problem is in the heater block. If both hoses are heating up then the problem is probably in the climate control knobs or wiring that controls the blend doors or may even be the blend doors are broke and are not opening correctly to allow heat into the vents. This could also be a problem if the ac does not get cool either.

the clicking noise is from the Heater/AC air temperature control bleed door, either the blend door shaft is broken or the actuator gears are slipping over eachother that move the door, these used to be cable operated, an electric motor was added years ago for more precise temp control of AC and Heating, to repair this the entire dash must be removed, this requires a factory repair manual and is a 10-12 hour job, very difficult job.

are you sure it is not the temp control on the heater control panel that's bad?
please rate if this solves your issue.

A/C Electronic Blend Door Actuator The A/C electronic blend door actuator is located on the rear of the A/C evaporator housing assembly.

• Its function is to move the A/C air temperature control door on command from the control assembly.
• The A/C electronic blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the A/C air temperature control door.
• A 5 volt signal is applied to the ends of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the control module and is matched with the wiper voltage of the module potentiometer. The printed circuit board then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the control module wiper voltage.

A/C Electronic Blend Door Actuator
Removal

1. Disengage two push pins retaining instrument panel insulator to instrument panel. Disconnect courtesy lamp from instrument panel insulator.
   
   1. Remove floor console. Refer to Section 01-12 .
      
   1. Working from under instrument panel, remove two retaining screws and metal cover from A/C evaporator housing.
      
   1. Remove A/C electronic blend door actuator electrical connector.
      
   1. Remove three remaining retaining screws from A/C electronic blend door actuator.
      
   1. Pull the A/C electronic blend door actuator away from the A/C evaporator housing for a distance of approximately 25 mm (1 inch) to disengage it from the A/C air temperature control door.
      

Is the heater working? Turn the A.C. off with the car at an idle. Turn the A.C. on and listen for the compressor to turn on. (should hear a click under the hood and the motor should change pitch. If no noise, the compressor is not comming on. The o-rings were bad about leaking on these cars, letting out all the freeon. If there is no freeon, the low pressure switch won't let the compressor run.

the door opening & closing on Max a/c is the inside/outside air intake door.
The temp blend door is the one you are concernd about. It says you have to remove instrument panel for access. ouch!!!

-------------------------------------
A/C Electronic Door Actuator Motor
The A/C electronic door actuator motor (19E616) is located on top of the A/C evaporator core housing assembly.

• Its function is to move the A/C air temperature control door on command from the control assembly.
• The A/C electronic door actuator motor contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the A/C air temperature control door.
• Battery voltage is applied to the ends of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The actuator wiper voltage is sent to the control module and matched with the wiper voltage of the module potentiometer. The printed circuit board then drives the actuator motor in the direction necessary to make the actuator wiper voltage agree with the control module wiper voltage.