Air controls now only blowing super hot air 2008 LE

Stuck on heat all the time is probably not a bad thing for today, but you probably will want that fixed before Spring gets here (assuming it ever will!).

The dash assembly is in two parts, with the knob control panel in front, and the AC Amplifier behind that. The dash assembly sends a signal to the airmix damper servo controller. That servo motor moves the damper that directs air to go thru or around the heater core (little radiator) in the HVAC box behind the center cluster. The LE model only has one temperature control servo & damper, and that motor unit is located on the right side of the HVAC box (at the left hand edge of the glove box). When these motors fail some people have report hearing a 'clicking' sound as the unit searches for the right position.

I can post some drawings to help you find that motor. Step one would be to see if it is receiving a signal from the dash controller. If you are lucky, it's just a dead/stuck motor. The dash modules can cost you something like $500, while the motor is maybe $100.

How about the rear AC? Is it responding to your change in temperature request?

Want to trade? I am so sick and tired of snow & cold.....

I would tend to think that if the rear is working properly, then the basic microprocessor logic of the HVAC head unit is probably OK. It could still be a connection or wiring problem, but I wouldn't go and spend money to replace the control panel just yet. More likely it's just a motor problem on the HVAC box.

So lets start with this. These pictures are from the drivers footwell. Dual front (XLE/Limited) vs. single temperature (LE/CE). Unfortunately I don't have one from the passengers side. Next time I change the cabin air filter, I'll have to snap a few. But from the drivers side you can see what the servomotor looks like. It will be in the exact opposite position on the passengers side. If you remove the glove box door (like for changing the cabin air filter) you should see it on the left. Don't confuse it with the other damper motor that determines fresh air vs. recirculate air (air inlet). If in doubt, change the dash control and see what the fresh/recirc. does.

This is the drawing from the split temp control system, so it shows both the drivers and passengers air mix (you will only have the passengers side and it will control one large flap within the box). There is a single electrical connector on the servo motor. Another night I'll see what I can find on the pinout. Start with simply monitoring for any motion of the attached cams when you change the temp control. It's always possible that the motor is fine but the cam levers are not engaged, or the flap and shaft within the box are not connected.

There is a piece of ductwork that brings floor heat to the passengers side footwell. Removing it might give you more room to access the servo motor. 87212D. Looks like a single screw or clip holds it in.

Here's a better image:

Here's the basic test for server motor functionality:

OK, I've got some thoughts on this. Let me see if I can articulate it.

The flap is controlled by a servo motor. A servo motor is part of a closed loop system in that it provides feedback on it's position. The master control takes that feedback and adjusts it's 'request' signal to the motor to move or stop moving. Lets imagine that the temperature control on the dash has 20 clicks from COLD (at 0) to HOT (at 20). Move the dash knob from full cold (0) to midway (10), and it sends a signal to the motor to move from full cold towards hot. How far will the motor travel? Until the position monitor on the motor tells the dash controller that it has reached half way. How does it do that? It sends a signal to the variable resistor (terminals 1,2 & 3), and watches for it to reach the 50% mark. Once the dash unit gets the signal that the correct position has been attained, it cuts the power. What if it never gets told that it's successfully left the cold position and moved to the midpoint (ie. the position monitor is broken)? Chances are it might continue to push towards heat until doomsday because it's never told to quit!

So either the dash module has lost it's hearing and isn't obeying the servo motors positional signal, or the positional sensor circuit is broken on the motor, and the signal is never sent.

In the basic motor test you followed, you applied positive and negative voltage to terminals 4 & 5. The motor turned full one way, then the other. Terminals 1, 2 & 3 are a simple variable resistor circuit that's used by a sensing voltage to determine the position of the motor arm.