Just came back from the dealer with the sad news of the $1500.00 to "fix" my climate control problem!
Couple of years ago, I had repairs done to my car. After they returned it, I noticed the flashing temp display on my control. As time went on (weeks) it stopped and everything seemed to work "ok" again. I had to replace my battery Monday. On returning home I noticed the flashing display again, and there was no heat! I took the car today a dealer to see if he could "read" the codes and see what was going on. The repairman said that this model year you can program the module. He was able to reprogram it. If it happened again then they would have to tear apart the dash and such and start checking wiring, and both modules. Each mod is approx $500.00 to replace plus another $500 for labor (least)! Can't afford that. I have noticed that after I drive the car and get it up to normal temp, that if I shut the car off and restart again, it starts putting out heat and working correctly. After about 20 - 30 seconds, as soon as the display starts to flash, I can hear that a door has closed or moved by the sound of the blower and then cold air start coming out. If I repeat the same steps, stop and restart it will do it again. Even if I shut down the ac/heater all together and restart, the outside temp will start flashing after 20 - 30 seconds.
Does anyone have any ideas? I really need help. I have to go job hunting and it'* going to get into the 20'* starting this weekend! HELP PLEASE!
PS I just found the Climate control diagnostic but haven't attempted to get the codes yet.

First off..what do you expect from a dealer?

Secondly.. hold off on that second or third job. These parts are cheap and the dealer is simply not over the top super educated like this specific car forum.

It'* flashing because it'* pissy. The system will get pissy for about 50 drive cycles or ignition cycles. About the time you are used to the flashing, it'll be gone.

The most common issue is the air mix actuator breaking. It has plastic gears inside and over enough years the main one develops a split in it. Rockauto sells the actuators relatively low cost. From there we can walk you through replacement w/o taking the dash off. Yes..a little bit of yoga and braille will get you through. otherwise, it'* not a bad situation. I've done many.

First thing to do is pull the glove box liner. Looking at the thick metal dash brace..There is a hole in the leftish area of it. Look through that hole until you see the metal rod with white plastic arm. That'* the arm of the air mix actuator. Moving the temp up and down (allowing for movement time of about 30 seconds per change) look for free movement. Any clicking, fighting or jerky movement means you'll be joining the ranks of us that know how to change these out.

Please go check and report back.

If the issue isn't this item, there are only three other main pieces. HVaC programmer, headunit and temp sensors. All those are pretty easy to swap.

Hey BillBoost, 2 questions concerning the air mix acuator. I had the arm off of it tonight to see if I could calibrate it, and with the arm off, I noticed when I moved the acuator with a screw driver over toward the cold side or toward the drivers side, and moved the screwdriver out of the way that the acuator snapped shut, back over to the hot side, back over to the passenger side. Does what I just typed make sense?????? Is that the vacuum working or should it not snap back like that, or is their supposed to be a vacuum for both ways.
Also, since you have done alot of these, Why isnt it possible to remove the bolts that are behind the glove box, move that black support out of the way, and replace the acuator.
If you need more explanation or have questions, I can probably jibber some more......lol.
Thanks

I'm not sure which part you were pushing on. The door leveler should move freely. The actuator should not move unless it tries to move.

Downside is you didn't answer my question about if that arm moved smoothly on it'* own. We still don't know if your actuator is broken. There is no vacuum on this part of the system. Vacuum is used to direct the air to various vents etc by closing other flaps. This one is actuator/motor controlled for temp.

Ok..... The part with the threaded arm moved freely back and forth when it was hooked to the plastic arm..... I watched it when it was hooked up and I watched it when I unhooked it.....
The part that I was pushing on was the arm that had the plastic arm and was at the end of the threaded arm....That I can see through the hole in the dash.....
It was stuck toward the passenger side of the car..... When I took my finger and tried to push it toward the drivers side, it was harder to push, and when I let go of it, it snapped back toward the passenger side.
Is that the acuator????? thank you sir.....

The actuator is on the passenger side with the metal rod connected to it. The threaded end of the rod then snaps into the arm that controls the blend door. The blend door arm should flop freely when the actuator'* threaded rod is popped out of it.

Sounds like you may have a blockae in the heater box.

I have the same problem. About a year ago now my car started doing straige things like slugish driving, back firing, the SES light would come on one day be off the next and the car would run fine for a while. one day I was driving and noticed the electronic climate coltrol oudoor temp light was flashing (always 34 times) from statup and my heat was on with the control off. Sometimes the A/C would be on even though the control was set to heat. After 2 mechanics and finally a dealer diagnosed the main PCM. Had it repaced back in May this year and everything was fine until I replaced a weak old battery about a week ago. After I installed the battery the flashing started again (34 times) and the SES light came on and now is off with no code in the history, but a new problem apeared, all of the lights dim and come back including the blower motor like a power serge. So I can't tell if I have double trouble or if its the PCM or the modual. I was told by a mechanic the PCM did'n reset right and it has to be reflashed. Could this be the problem?

Its a '94 SSEI Super Charged 3.8 vin 1

Finally. I was able to get into the car and check the air mix actuator. Here is what I found.
I drove the car to warm it up so it would make a difference running the temperature up and down. Just before I returned, there was a small about of heat coming out the vents! I removed the glove box liner and ran the heat up and down. On the first attempt I thought I saw some jerky movement. I repeated the test multiple times with only smooth results. I've stopped the car, restarted with the same result.
I have noticed on several occasions that when I start the car cold, and the control is set to auto, that the heater will start. Never did that until the engine warmed up slightly.
Also, it seem like it take 1-2 minutes before the air moves from say defrost, down to the floor or the vents. It will eventually move, but it seems as though most of the air is directed to the windshield.
Is there any hope?!
Also the heat sensor inside the car is clean or appears clean.
Thanks

Hello All,

I finally figured out the problem with people out there with the flashing ECC outdoor display and screwing up the heat/air not working after diconnecting the battery. After talking to a couple of GM mechanics and reading posts from this site I solved my problem and it was so easy I'm kicking myself. If you have the same problem I had to do the following,

1. Locate your outdoor temp sensor (open hood and look down in front center of the radiator)

2. Disconnect the wire from the sensor

3. start the car (no outdoor temp) turn the ECC on the inside temp flashed as it did for me before.

4. turn the car off after around 3-5 min.

5. Reconnect the temp sensor and start the car and GOOD GOD no flashing light and the heat and air worked as it should.

after I did this my ECC works fine I drove the car 5 times shuting it off and restarting as I went and its fixed, no taking the dash apart or the glove box either or dealer repair cost. If this works for you please post a reply. Why GM could not figure this out is beyond me or there doing the same thing in the shop and charging $$$ to do a simple job. Good luck.

This is an incredible find! What is the logic behind disconnecting the outdoor sensor?