Defrost

[old blue 86]

Heat question.
My heater shifts from heat to defrost but
does not completely shift.
I only shifts about 50%.
Any thoughts?
Thanks

[77 350 Shorty Wide]

Good Morning, If you mean the lever on the control only moves half way? You could check to see if the cable is long enough, maybe bent or binding. There could be an obstruction in the heater box not allowing the door to fully move or it could be hanging up due to corrosion. Good luck.

God Bless, terry

[old blue 86]

This is a air truck with vacuum controls.
It is getting vacuum but is not moving full stroke.
Any one have any pic's of that part of the system?
thanks

[motornut]

Hi does it quit blowing elsewhere?
If not it could be this flap/door.
or there is a spot on the floor/defrost actuators to make it stay some up or down
I put it in the middle hole,all up or all down

[old blue 86]

Every thing seems to work as it should except the door that sends
the air from the floor to the defrost does not close all the way.
That leaves half the air going to the defrost and half to the floor.

[old blue 86]

Any thoughts on why this would happen?^

[motornut]

The actuator for that function has 3 spots for flow.
Dependingon the hole used inside the air box.
It will do that

[motornut]

The one at the gas pedal

[old blue 86]

I have owned this truck since 2000, It was a 1 owner.
Up until last year or so it worked as it should.

[old blue 86]

Originally Posted by motornut

The actuator for that function has 3 spots for flow.
Dependingon the hole used inside the air box.
It will do that

Can this be checked with out taking the whole dash apart?

[motornut]

Yes
Remove the hose there ,plug it,apply a separate vacum to the actuator.