Hi everyone.
Let me start by saying that I have searched and read every post regarding this that I could find.

The unit will switch between (for a/c or heat) upper, and lower, just not thru the dash vents.
Temp control works well aslo.

I have vacuum going thru the firewall to the purple line feeding the programmer. With the engine off it holds vacuum as does the canister, but with the engine on it won't which is why i beleive I have a leak in or after the programmer. I have 20mmHg coming into the programmer.

Thanks for all your help,
Popa Tim

Tim, first to beat Willwren on this one, plesase put your car'* year and trim level in your signature. For example mine is a 95 SSEi or a 97 SSEi. Some problems are more common to certain levels.

There'* a couple of people as you have seen with the same problem. You already diagnosed this very well and have everything ready. You're next step would be to check the vacuum at the door itself to see if the programmer is bad, or if there is a door problem.

Good luck and please post the findings for the others with the same type of problem

Does the 'door' have a name I can search by or what color is the vac.line that controls the 'door' and I will test that. I'll do a search tooand see what I can come up with.
I have not come across that info in any of my previous searches.
Thanks,
Popa TIm

ps - so far all diagnostics for the 97Bonne'* have matched up to what I've found on this car. I'm still looking to pick up a Bonnie for myself. Test drove a 95 today but it needed the UIM and the a/c was shot.

I have the same problem and so does echossi and nick. Its hard and its involved. I still havent fixed mine yet. Would llove to chat about it some time. I feel it may not be a vaccun line leak after the hvac unit. It could be the actuator that moves the door itself. Ofcoarse Im noo professional. Take a look at Zero to ghetto in less than a half hour in the Lounge I think to see what I did temporarily. Talk to you soon.

The proper name for what you are looking for is Bi-level valve vacuum actuator. I usually call them air[flow] diverter actuator or diaphragm. According to my 93 manual, the LT GRN and WHI vacuum lines control the airflow. Vacuum to WHI opens the floor vent, vacuum to LT GRN opens the dash vent, no vacuum to either is bi-level.

I like your testing so far and it points to a stuck actuator. I'm sure your next question is going to be "where is the actuator". Well, I'm not too sure. I've always had the cars thoroughly disassembled and didn't pay too much attention to their locations. In the following pic, you can see two actuators. One is to the left of the two large openings in the middle of the dash area and the other is directly below that one.

Now, how do we unstuck it if it is stuck. That would be the question. Somekind of manual override. Or super lubricant. Maybe a jimmy or shake somewhere. Things usually don't get stuck without a reason. maybe old crusty parts. Or some build up. What could cause this "being stuck. I know I know. I have to check the vacum line to the doors. That wouold be next. But then if they are stuck, what? I wonder if I call pontiac and ask some service mgrs if they have solutions to this problem would they help? (thinking aloud) Im sure they know. To many of us have this problem. And I bet there is a procedure they use to determine the cause and then repair it. ** I now have a quest**

Yes, Go forth Grasshopper..........

Yes, check the vacuum at the end of the line. That will determine if the vacuum actuator is good or bad. If it'* bad I believe it'* a mere replacement that is needed. Not that it will be easy to get to, but Randman can probably give more insight. He'* something like the resident expert on the airboxes.

I'll keep checking. Tomorrow will be a good day I think.
So, what are the Red and Black vacuum lines that come out of the programmer controlling ?

Thanks,
Popa Tim

ps - can someone check to see if they hold vacuum on the line that feeds the programmer when the engine is running. I only hold it while the engine(&ecc) is off.

Hello again.
Yes I'm still at it...it took me 2 hrs to tear out the dash. Its 94 out and I REALLY miss the cold air blowing on me...LOL

Heres it what I have so far"
the divierters all checked out ok and held vacuum so I backed all the way back to the lines as they came out of the programmer.
From the programmer to the airflow diverters, for lack of a better term:
Vacuum on the
Green line puts air out the defrosters with a little out the bottom.
White line put air out the bottom with a little out the defrosters
Neither white nor green will produce a little air out of both defrosters and lower
Black line (looks like navy to me) puts air out of the vents
Orange line close the outside air (turns on recirc)

My Haynes manual doesn't go into this area at all.
I am at the point where I need someone with a service manual to assist or email me pages I need for troubleshooting. I don't know if my eec unit on the dash is putting out the proper signal or if the problem is in the programmer itself.

Thanks All!!
Popa Tim