No heat to floor

[Diesel]

When on heat no air blows out the floor vents. What's wrong?

[TWorline]

A couple of things comes to mind:

The actuator rod has come unhooked from the door.

You have a vacuum leak to the actuator.

The control unit went bad.

You have a nest or other debris in the heater box which is stopping the door from moving.

[Diesel]

Nest is really possible. In terms of vacuum - what line do I check or replace?

[TWorline]

Un latch your glove box so you can see the heater box, with the truck running switch it from defrost to heat and watch the diaphragm on the left side for movement. Here is an article on removing the heater box: http://www.dieseltruckresource.com/dev/remove-hvac-box-t248580.html?t=248580

[quickie70]

I was also wondering about this... except mine is in the defrost. Mine was a farm truck and sat in the field for the last 8 years, and has all sorts of weird junk that come out of the vents when the fan is running. I'd be willing to bet I've got a bunch of that junk in there, as well as some issues with the vacuum. Which line should there be vacuum on when it's running?

[bmoeller]

Too bad I didn't see this earlier. I got vacuum hooked up to my HVAC controls tonight. Only had the truck for about 17mths. Opened the glove box to see the actuators and such on mine. They're all working now. Still can't turn the heat off, without closing off the ball valves I installed. Cable is attached on both ends, and the door moves. Probably just not moving the blend door far enough.

They lines are color coded. With the truck running, you can pull hoes off by hand to see which one is supposed to do what, if it has vacuum.