99 PA a/c won't blow through dash vent

[nathansmithusa]

99 PA - When I turn the A/C on, in will only blow to my feet or through the defrost vent, it will NOT blow through the dash vent, regardless of the setting. Does anyone know what could cuase this problem? I was thinking of replacing the A/C Heater control unit, but I'd like to get some input before spending all the $$$ for trying to shot-gun a fix. The temp settings work fine for heat or a/c.

[TopherS]

I had a similar problem a few years ago and it had to do with the mechanism (actuator??) that opens/closes the vents. The head-unit was fine, but the air only came out of the floor. I had it fixed at the mechanic's shop, so I can't tell you exactly where the problem was...only that it was in that mechanism.

Has worked fine ever since...but, now my blower fan is noisy...

Good luck

[big white bufflo]

check for vacuem line broken going to the fire wall then remove the hush panel and check the acuator above the center hump that is the one that controls this function

[nathansmithusa]

First, thanks for the info. What and where is a hush panel?

[big white bufflo]

the hush panel is the thing that covers all of the under side of dash

[imidazol97]

Originally Posted by nathansmithusa

99 PA - When I turn the A/C on, in will only blow to my feet or through the defrost vent, it will NOT blow through the dash vent, regardless of the setting. Does anyone know what could cuase this problem? I was thinking of replacing the A/C Heater control unit, but I'd like to get some input before spending all the $$$ for trying to shot-gun a fix. The temp settings work fine for heat or a/c.

I would be surprised if the 99 still used any vacuum. I would expect that the changeover was made to all electric controls. You won't know until you take off those thin plastic panels under the dash and look to see if you have electric controls or a combination of electric and vacuum.

What you need to do is operate the controls with the key ON while you are under the dash looking up from both sides of the box that controls the air. The electric actuators have white plastic arms and you can see if they are moving when you change the appropriate buttons on the dash.

If I've got the drill right, there will be one for the driver's side blend door to mix the air to get the right temperature, one for the passenger side blend, one for the air direction to change from floor to dash to defrost, and one for recirculation of air from the passenger compartment back through the system.

[bigsky]

Originally Posted by imidazol97

I would be surprised if the 99 still used any vacuum. I would expect that the changeover was made to all electric controls. You won't know until you take off those thin plastic panels under the dash and look to see if you have electric controls or a combination of electric and vacuum.

What you need to do is operate the controls with the key ON while you are under the dash looking up from both sides of the box that controls the air. The electric actuators have white plastic arms and you can see if they are moving when you change the appropriate buttons on the dash.

If I've got the drill right, there will be one for the driver's side blend door to mix the air to get the right temperature, one for the passenger side blend, one for the air direction to change from floor to dash to defrost, and one for recirculation of air from the passenger compartment back through the system.

These actuators do not have the white plastic arms, but rather an axel that you can observe from the back to see if it is moving.

To get to the mode actuator you have to remove the driver's blend actuator. And first is a plastic wire? conduit with a screw way up that cannot be seen. All accessed under driver's side dash after removing bottom "hush" panel.