Marccus
New Member
I get hot air from the defroster vents when the heater/AC is off. It doesn't come out really strong like when the fan is on - almost like it is "leaking out".
This happens randomly. I'll put my fingers up by the vents over the dash near the front window and can feel the hot air come through. When it doesn't happen I feel nothing come out the vent.
It neither case do I feel or hear the fan (blower?) operating.
I searched this problem before and some stated that the VBCM was going.
I just replaced it with a new one and the same problem occurs - in fact it is worse!!
Perhaps the door that directs air to the various options (panel, defroster, floor, etc.) is malfunctioning and setting itself in the position to direct air from the fan to the defroster vents when the electronic control module is set to off.
Also there is a another door which lets air in from the outside which I can access from the engine compartment near the firewall. I just have to remove the plastic trim on top.
(I know one of these doors is the "blend" door but I forget and don't have access to my shop manuals).
I noticed that the spring that held this door shut had disintegrated from weathering and rust.
But the problem of hot air venting from the defroster vents had been going on even when this spring was intact.
Should I replace the spring or not bother? I doubt that the spring is available as a replacement part so I'll have to come up with one that has enough tension to hold the door shut but not to prevent the actuator from opening it.
Lastly, the actuator needs to be replaced as w whining sound came on every time I started the engine. But the sound is gone now - I guess it burned out.
But replacing this part is a big job. Perhaps replacing this part will solve the problem of hot air venting through the defroster vents.
'89, 282K, stock
This happens randomly. I'll put my fingers up by the vents over the dash near the front window and can feel the hot air come through. When it doesn't happen I feel nothing come out the vent.
It neither case do I feel or hear the fan (blower?) operating.
I searched this problem before and some stated that the VBCM was going.
I just replaced it with a new one and the same problem occurs - in fact it is worse!!
Perhaps the door that directs air to the various options (panel, defroster, floor, etc.) is malfunctioning and setting itself in the position to direct air from the fan to the defroster vents when the electronic control module is set to off.
Also there is a another door which lets air in from the outside which I can access from the engine compartment near the firewall. I just have to remove the plastic trim on top.
(I know one of these doors is the "blend" door but I forget and don't have access to my shop manuals).
I noticed that the spring that held this door shut had disintegrated from weathering and rust.
But the problem of hot air venting from the defroster vents had been going on even when this spring was intact.
Should I replace the spring or not bother? I doubt that the spring is available as a replacement part so I'll have to come up with one that has enough tension to hold the door shut but not to prevent the actuator from opening it.
Lastly, the actuator needs to be replaced as w whining sound came on every time I started the engine. But the sound is gone now - I guess it burned out.
But replacing this part is a big job. Perhaps replacing this part will solve the problem of hot air venting through the defroster vents.
'89, 282K, stock
