Hot air only flows to vents, not to defrost?

Question

I have a 1995 VW Jetta GL, 2.0 engine, 5 speed, a/c.
My heater won't switch between defrost, floor heat or vents. It's stuck on the vents and I can't seem to find out why.

1. I have torn apart the interior panel and disconnected the cables and worked them manually (no help).
2. Everything gets hot and cold and the fan motor works great but it's all just stuck on blowing the air out of the vents.
3. When I switch it to defrost, the air from the vents slows down a little but not enough to defrost the front window.

What could cause this?
Please help; it's taking forever to defrost my car in these cold mornings.

Answer 1

Vent Doors in your HVAC system are not working properly

You have various doors in your system to direct air to appropriate places as you change the settings on your dash.

When you want air to come out at the floor and you change the setting, a door closes off or opens up appropriately in your system to direct the air to the correct location.

The internal door to your defrost is not working properly. In your car there is a manual system that opens and closes the doors. You will need to find the door that is not working properly and troubleshoot the little arms and what not the operate it from dial on your dash.

In many cases, and probably yours too, you will need to disassemble part of your dash to gain access to the mechanisms to fix this.