(2nd Generation) FAQ: Help! My HVAC is cold on one side, hot on the other!

[GP1138]

Unfortunately, there's really no great way to get at them. Contort your body, bend your wrist backwards, and have fun.

I've had many dates like that.

[axisofjustice9c3]

Does this apply to a '98 Lumina? I bought the car with a locked up compressor, put on another compressor and had room temperature air with A/c on cold, and hot air with it on heat. I bypassed the heater core to see if heat was bleeding in from there, and it was. After a quick bypass it was freezing on the driver's side, slightly warmer on the passenger side. The dual zone was always funny acting (can't really describe), and with the heat bypassed I didn't use it much, so I can't really give much info on symptoms. Suddenly, after three weeks of good cold air (FLORIDA, ugh!!!) it decided to blow ambient air temp, which could be heat as it is still bypassed. The compressor still kicks and runs and doesn't cycle fast (on/off/on/off), so I want to say that since it is all new that it still is working but is having HVAC control gremlins (o-rings, charge, oil, lines, compressor, orifice tube, reciever/dryer all new).

[bmaverick]

This is a common actuator used by GM, some Fords, some Chryslers and often Jeeps. A few of the transplant vehicles use these as well like some Toyotas and Nissans.

With that said, these actuators are popular from the late 1980s to the present. The gear guts are usually the same, only the PCBs are somewhat different depending on how the actuator is used. The little blue gear is the pot. Some of these don't have a blue gear pot control and can be easily fix by swapping out the cracked gear from a donor actuator.

The large gear that tends to crack at times comes in two flavors; one with a metal wiper contact (w/o blue gear pot) and one without the metal wiper contact (this has a blue gear pot or none at all). So, getting any variant of the actuator and to swap out the cracked gear would save big dollars.

If you plan on swapping out a cracked gear, take note the position of the big cracked gear and the position of the blue gear. Then just swap in a new big output gear from a donor actuator by lining up the bump tab if needed to the old position.

These actuators are used in other applications as well and/or other industries too. (Sunroofs and rear tail-gate power window) (Solar panel positioning systems, solar water valves and small dish satellite communication receivers) (RV industry for water valves) (Aviation and Marine for HVAC climate controls).

Three companies make/made these actuators. One is in TN (Saia-Burgess), the other in Asia (Worry) and the third company quit producing them by the late 1990s (Eaton).

These actuators can be had at a reduced price new. Go to any Mopar parts and service counter and order one without the 12m/12k part warranty. This usually cuts the dealer price in half or more. This works best since you get a newer actuator. However, you are buying it "as-is" with no return option. Thus far, I've never been burned with a bad dealer part yet. It's taking chances I know, but I do inspect the package first before leaving the counter. Some dealers will not do the bare part only no-warranty sale, so find one that does.

The other option is a bone yard for a W-body or other vehicle that uses these as mentioned above.

[axisofjustice9c3]

If ordering from Mopar, what are the equivalent parts #'s?

[mhildebrand]

I have the problem that the passenger side controls in my 96 CS dont do anything.. What ever the drivers side is set to, thats whatthe passenger side goes to. Same with the passenger button selected or not selected. Any ideas on this?

[tssegard]

I have a 99 Buick Regal and it doing this too. The display has not worked since we bought it but the climate control worked fine. Then a few months back the dual would not change. It blows HOT air out of the drivers and cold out of the passengers. You can see the temp sometimes so I know it is set at 60*. I pulled the glove box out and found the part but before I mess with it i thought I should check on here. Do you think it is the Drivers side that is the problem since that one has the wrong temp?

Thanks in advance!
Sarah