: Dual Zone Problem

11-24-08, 12:07 AM
I got a problem on my dual zone climate control. Basically... the passenger side is always blowing warm air even though the temp knob is at it's lowest setting. It is very noticeable when comparing with the driver side vents. It does make grinding sound when I turn the temp knob. So it seems that the motor or mechanism that controls the valve cannot fully move! It does get hot when I turn the knob to the hottest setting.

Does anyone know what this part is called? Or has anyone ever had a similar problem that can give me some info on what interior parts I would have to remove in order to access this area that needs attention? Is this problem normally fixable or would they require a new part?


11-25-08, 01:46 PM
There are several posts here on this subject. The problem is usually a loose screw on the actuator motor shaft.

I did a quick search and pasted from someone else. However I remember there were even better instructions deeper (I fixed mine in 2006) with repair and even a suggestion to prevent it in the future. It's actually a quick fix, just hard to get to. I suggest a search on the forum for 'heater actuator' and 're-sync actuator" as you will have to tighten a screw and then use the re-sync procedure to get them back in proper position.

"They are little electric motors that rotate a lever to open and close the heat box and floor vents. I saw three of them of them on the passanger floor board near the floor tunnel towards the firewall on the inside of the Catera. If you have no heat anywhere, the problem probably isn't these actuators. Remove 3 plastic screws from the black panel under the glove box. You will see a pear shaped black cover against the transmission tunnel. Pull it off to reveal the passanger floor vent actuator if you don't have heat on the passanger floor. You can remove the two screws to remove it and check to see that it moves when you switch the passanger floor heat on. You will see two other round silver & black actuators above this one. I believe the one on the tunnel activates the floor vents on the driver side, you can feel the lever move with your finger on it when you activate the heat on the drivers side with your other hand. The third and highest activator that is on the firewall side opens the heat box I believe, you can see the lever move up and down when you turn the heat on and off. Note that it is possible that these actuators are moving but out of allignment and not pushing the levers that they are supposed to."

Hope that helps.