1996, Dual ACC - passenger side heat always on

[Littlebike]

Slowly but surely I am getting my wifes car back in to fighting condition - thank to the help here it is running great now - so it is on to minor irritants; HVAC.

Her car has dual climate control with with passenger controls on the passenger door panel. For the past year it has been putting out high heat to the passenger side about 90% of the time - sometimes it puts out blended air - but there is no consistancy or pattern.

This condition seems to be completely independent of what the master controls are doing with exception to fan speed. This usually results in one really hot passenger and one semi cold driver (cold air to try and counteract the passengers hot air).

I have looked behind the glove box door to see the two actuators move, and they do move, though, I wonder if they move with any consistancy and I doubt my wife wants to drive around looking into her glove box periodically.

Can anybody tell me what these two actuators do?
Is there another one I cannot see that adjusts passenger side blend?
I have heard two strange sounds coming from the dash but inconsistantly:
- 1. Clicking sound
- 2. A rythmic swish/sucking sound (possibly vaccum or poorly calibrated door).

Any help would be greatly appreciated, pictures are even better!

I hope to keep this car on the road another four years!

[HotZ28]

The passenger side blend door could be part of the problem, but I would check the refrigerant level first. Cool on the drivers side and warmer on the passenger side are one of the first signs of low refrigerant on this particular system. Here is a view of the components’ within the dual zone system. Get that pressure tested first & report back with your findings.

[Littlebike]

I know issue has to do nothing with AC, that badboy will throw AC like mad.... but only on one side. In the winter when you want the car at a nice 72* the passenger side is near 90* or more. Your feet sweat in the winter.

Going by the graphic above I can saw with great certainty that the "Passenger Side Air Mix Valve" is reluctant to move from the FULL FURY OF HELL HEAT mode to the "happily blended 72* mode" or anything in between.

The real question is, where is that valve?

[HotZ28]

Originally Posted by Littlebike

The real question is, where is that valve?

It is right in front of you when you remove the glove box, the lower actuator. With the glove box removed and engine running, move the temp control from full heat to full cool and watch for full movement of both actuators. They should shift the full stroke. If not, you may have a problem with the lower one.

[Blue Bowtie]

Open the glove box, release the detent on either side, and allow the door to open fully downward. Remove the glove box lamp and electrical connector. Remove the screws along the lower edge of the glove box door hinge, and remove the glove box door:



Look toward the top of the photo, near the bar code label. You can see a small threaded rod / linkage connected to a white plastic arm at the right end. The driver side / main damper motor is what drives that white arm. If you look closely, you'll see the threaded rod is disconnected at the left end. It should snap/lock into the smaller white plastic clip on the damper door lever. You can start the engine, set the main controls to AUTO, and disconnect the threaded rod from the damper arm (as shown). Operate the main temperature controls to full heat and full cool, and make sure the motor moves the arm.

If you manually move the damper, you should be able to feel the discharge temperature change at the driver side or floor outlet from the "FULL FURY OF HELL HEAT" mode (nice one) to the "THERMALLY NEUTERED BRASS MONKEY" mode. If not, there may be a problem with the damper itself. If it works properly, manually set the damper to full heat, set the motor control to full heat, and connect the linkage. Try the main temperature controls again to confirm the operation.

Do the same thing for the actuator on the lower edge of the ductwork. Set the main controls to AUTO, and disconnect the threaded rod from the lower damper arm. Set the passenger side controls to full heat and full cool modes and observe the damper arm. Manually move the lower damper to confirm it is intact and actually controlling temperature at the passenger outlet, and set the controls and damper to full heat. Reconnect the threaded rod / linkage and check operation.

[Blue Bowtie]

Now that I think about it, I may have that backward. The upper one might be the passenger side damper, but I can't recall with any certainty. I believe the upper door was the larger one, which would be the main door.

[Littlebike]

Thank you so much! That is exactly the type of information I am looking for.

Now I have my Sunday plans figured out - work on the car!

[jgeorg]

Littlebike,

I don't mean to highjack your thread, but I have the opposite problem with my 02. What might be causing this? I've pulled the actuator out of the passenger side and seen it work. Is there an actuator on the driver's side and where can I find it or get to it. The passenger side climate control doesn't work. Again, apologies for jumping into your thread.

Jerry

[Littlebike]

I monkied with this last weekend and determined the passenger side damper is functioning, though, but not to it's full potential. I watched it sweep from full hot to not quite so hot - never got to cool/cold air.

BTW, it is the actuator connected to the horizontal metal rob in hte lower center of the above image.

Is there a possibility that it has become miscalibrated? If so, is it as easy as disconnecting the actuator from the metal rod, adjusting both to the same extreme and reconnecting? If so, how do I disconnect?

Thanks

[Blue Bowtie]

The actuator rod clips into the plastic arm.