heat only comes out defroster

[97xltexpo]

even if i put it on panel, panel and floor, etc it only comes out the defroster anyone know what that could be

 

[JUST4FUN]

HVAC has a vacuume leak somewhere , check under the hood by the battery

 

[Stoned06]

It is usually a bad vacuum line attached to the controls, or a blend door motor that goes out.

 

[tonydiv]

I thought that the blend door regulated the hot / cold mix. Am I wrong?

 

[ELVATO]

Does it do it only with heat?

 

[97xltexpo]

no it does it all the time i also have a missing mirror glass and backing plate (which i have ordered) and they are heated mirrors someone said that they may do it to but i will check for vacuum leaks, also i know i have a bad blower motoer resistor which i am picking up tomorrow

 

[01expedition]

did you ever get this fixed? mine does the same kind of it doesn't ever feel like it goes off panel but it still goes to the defroster too but the panel stays on. just wondering what I should be looking for a resistor problem or vac. leak.

 

[tonydiv]

I'm sure that mine isn't a vacuum leak under the hood. I have heat and a/c but as above, only out of the defrost vents.

I'm thinking that it may be one (or more) of the following:

Bad switch on dash pod
kinked/broken vacuum line under dash
blend door?


I'm going to pull out the switch pod and apply vacuum to the individual lines coming off the switch with a hand vac pump to see if it does anything. I'm also going to see if I get any vacuum to the switch.

 

[gfwelkner]

It's definitely not the blend door. That regulates the hot / cold mix, not the registers where the air is blowing. I just changed the heater core in my 98 so I was deep into this stuff. There is a vacuum junction point near the accelerator pedal. Just to the right of it and up a few inches. Try re-seating that connection. It should have some vacuum on it when you disconnect it. Another place to check is behind the A/C Heater selector switch. The panel covering it pulls off pretty easily. Then there are four screws for the A/C controls. I think they are 8mm. Re-seat the vacuum connection behind the selector switch and see if that does any good. Hope this helps.

Gordon