Heater Problem

[Mr Clean]

My heater works fine, the problem I'm having is I don't have any defrosters. When I move the handle to Vent, Defrost, nothing happens. I was looking under the dash, and the lever that is suppose to move the vent door isn't moving. Any ideas how to fix.

 

[89Suburban]

Either a cable or vacuum modulator isn't opening the door.

 

[Old77]

Does your AC work? If I remember correctly the defrost actually uses your AC to defrost the window....

 

[89Suburban]

What's the year make and model and is it ac?

 

[Irishman999]

I just had mine all apart for the heater core and it looks like that part is vacuum operated. The door that mixes hot air is mechanically operated, that lever is your hot and cold lever on the control panel. The selector on mine was all vacuum operated. Most likely there is a vacuum leak under the dash or in the engine compartment.

 

[Mr Clean]

What's the year make and model and is it ac?

82 LWB and yes it has AC

 

[Old77]

82 LWB and yes it has AC

Do you know if your AC is functional and is it functioning correctly?

 

[Mr Clean]

I just had mine all apart for the heater core and it looks like that part is vacuum operated. The door that mixes hot air is mechanically operated, that lever is your hot and cold lever on the control panel. The selector on mine was all vacuum operated. Most likely there is a vacuum leak under the dash or in the engine compartment.

The hot and cold, is working. It's the lever that controls the air and were it goes. I don't hear any vacuum leaks, I can manual move the door, but it won't move with the lever

 

[nxtlevl]

I just had mine all apart for the heater core and it looks like that part is vacuum operated. The door that mixes hot air is mechanically operated, that lever is your hot and cold lever on the control panel. The selector on mine was all vacuum operated. Most likely there is a vacuum leak under the dash or in the engine compartment.

X2.....................

 

[Mr Clean]

Do you know if your AC is functional and is it functioning correctly?

Yes the ac seems to be working like it should.

 

[89Suburban]

I just had mine all apart for the heater core and it looks like that part is vacuum operated. The door that mixes hot air is mechanically operated, that lever is your hot and cold lever on the control panel. The selector on mine was all vacuum operated. Most likely there is a vacuum leak under the dash or in the engine compartment.

x3

When you say you can move the door by hand, what is the lever connected to, the actuator? I would pull the hose off it and check for vacuum while you play with the heater controls...

 

[Mr Clean]

x3

When you say you can move the door by hand, what is the lever connected to, the actuator? I would pull the hose off it and check for vacuum while you play with the heater controls...

I don't see it hooked to anything. I went and looked at my Blazer in the back yard, and moved the same thing I hear a vacuum sound, I have really never messed with heater/ AC but just changing heater core, so I have no clue, what I'm looking for

 

[89Suburban]

Time to start taking **** apart buddy....if the truck is running and you move the controls around do you hear any kind of action under the dash??? You should be able to hear a door for the Max a/c move open and closed....

 

[Old77]

Take lots o' pics, though, and throw them up here

 

[RetroC10Sport]

Take lots o' pics, though, and throw up here

Throw up over by Old77 dammit, I don't want that!