Clacking sound coming from under the dash and A/C is stuck on defrost

Hi,

There could be a vacuum leak after the engine area or the actuator itself may be bad. What I suggest is this. Locate the mode actuator and see if there is vacuum to it when changing from floor to defroster.

If you look below, I attached the directions for removal and replacement. The actuator is near the accelerator pedal. Check to confirm there is vacuum. If there is, chances are the actuator is bad.

Let me know what you find.

Take care,

Joe

See pics below.

Hi,

If there is no vacuum, that is the likely reason it is in the default position, defrost.

At this point, if you have a vacuum pump, you could connect it to the actuator and see if by applying vacuum, you can change the direction.

Or, we need to determine where the vacuum is lost. I'm not sure if you have automatic temperature control or manual. I attached two pics below. The first is for manual temp control and the second one is automatic.

The pictures identify the connector on the rear of the control panel. Note that each vacuum hose is identified by a color. I need you to get up under the dash and locate the black vacuum hose to the controller. Disconnect it and start the engine. Is there a vacuum source provided by the black hose?

Let me know.

Take care,
Joe

See pics below.