Check the actuators under the dash. On older vehicles, the actuators used to be controlled by vacuum. If vacuum was lost, it would default to defrost. On newer vehicles the actuators are usually electric. I'll have to check about yours.
Jun 23, 2014 at 2:17 AM
JDL
✓Experienced Mechanic
16,098 POSTS
The actuators are vacuum controlled. I'd have to check for loss of vacuum.