96 AC Light Flashing code 02 Temp Blend Door Malfunction

[Corvette95]

Replaced the blend door actuator on my 96. Light was flashing and it was stuck on hot. Now I have MAX COLD and MAX HOT, sometimes in between works but the a/c light flashes a code 02 - temp blend malfuntion. Bought another actuator - same exact problem. Unhooked battery several times to reset. No change. Pulled the actuator out as I changed temp settings, it just wanted to go to full hot and "bounce" off the max position. CCM diagnostic in mode 34 shows 00 and -153 respectivily, mode 24 shows a little off from expected readings. I dont know where to go from here. Any thoughts?

 

[Schrade]

After you put in the actuator, and when you turned the key on, you should have heard the actuator calibrate, as it went to each extreme in range.

You did have the battery disconnected when you connected it?

 

[Corvette95]

Tried both ways. With it out, it goes to extreme hot then just "bounces" off the full hot position and stays there. Same with it set on 60 , bounces off full cold.

 

[Schrade]

Is your thermometer working?

The current temperature outside is a reference point in the range of the actuator. It reads the max point of range, and calls that '90', then the min point of range, calls that '60', then reads the air temp, and adjusts accordingly, regardless if the motor is running or not.

If it pegs on HOT or COLD, with no in-between, then the controller IS inputting to the actuator, but

...

 

[Corvette95]

Is your thermometer working?

The current temperature outside is a reference point in the range of the actuator. It reads the max point of range, and calls that '90', then the min point of range, calls that '60', then reads the air temp, and adjusts accordingly, regardless if the motor is running or not.

If it pegs on HOT or COLD, with no in-between, then the controller IS inputting to the actuator, but

...

I have followed diag tree in factory service manual haven't seen reference to outside temperature sensor , I haven't noticed if it wasn't working. I have a tech2 I will check in car display and outside temp value in tech 2. Anything else?

 

[Schrade]

When you say bouncing, each time you change the temp setting, are you meaning that the actuator is going through the range again?

If so, it sounds like it is not properly calibrating.

I thought that actual temperature was used in calibration, but perhaps not...

Without FSM, all we're knowing for sure is that it IS responding to the temp controller, even tho' it's pegging at each extreme.

:confused

Does the diags chart say to look for another DTC first?

 

[Corvette95]

outside temp is reading ok. The blend motor has "marks" on its facing in about the 10 and 2 o'clock position each being full hot and full cold respectively. The motor will go to either side and try to go further but just sits at the limit and "ticks" off the full range of travel as it tries to go further, like it skips a gear tooth. All three motors do this as full hot and full cold positions.

 

[Schrade]

Wow there 95... Sounds like the 'STOP' contact might be open, when the connection is made to 'STOP'.

Check the connector on the harness plug - not the actuator socket, and see if an individual pin is pushed back.

My '98 Electronic Control has 5 wires. 1, or 2, will carry the 'STOP' signal.

Check FSM for yours, to see if you can identify each lead at the connector. All 3 actuators CANNOT fail to send (or receive?) the STOP signal. It has to be in the harness connector...

 

[Corvette95]

I will check the connector in the morning, thanks for the help. I have had a call into Gordon Killebrews new tech web site that I am a member but havent gotten a response yet

 

[Corvette95]

connector was good , next step is to check wires going into programmer?

 

[Corvette95]

How does the programmer know where the temo motor is at? I know the motor sends a position back but has does IT calibrate itself?

 

[Schrade]

How does the programmer know where the temo motor is at? I know the motor sends a position back but has does IT calibrate itself?

Don't know exactly, but you can see a chip on the logic/printed circuit board in my actuator. It hits one stop, calls that 60, goes to the other stop, calls that 90, and divides the range into increments??? Then the actuator adjusts the door position based on internal temperature (and outdoor, for later GM's).



I think that if the actuator is CONTINUING to turn, even tho' it's at either end of the range, then a 'STOP' signal is not gettin' carried.

Whether the signal is not getting RETURNED TO the actuator, or if the origin signal FROM the actuator stop contact is not getting carried BACK TO the [ECM?] we don't know. But I bet it's one or the other situation.

Check the schematics in FSM, to see if the actuator terminals are ID'd, by name (feedback, or something like that), or if the leads themselves are ID'd. One of them will be labelled 'Hot at all times', or 'Switched power'...

Whichever THAT one is, is the source power for the initial calibration. The 'end of range' contact SHOULD send a signal to another terminal of the actuator, and POSSIBLY the other end of range will send the same signal to the same terminal, OR to another terminal.

You do have multimeter?

 

[Corvette95]

Yes, I do have multimeter, I will check and post. thanks!

 

[Corvette95]

BTW, if during the calibration cycle, it turns to 60 then 90, from MEMORY, I dont think mine is doing that cycle upon initial start up from battery disconnected. I think it goes to one side and stop which leads me to believe it not getting the signal that its at travael limit BUT the displasy shows its sensing its at maximum travel (either 00 or -153)

 

[Corvette95]

Here is the latest. The 96 blend door actuator is different (of course) .....see the little BLUE gear in your photo, thats what tells the programmer where the door position is, the 96 doesnt have that , it has a small dual electronic contact track below the BIG gear that move the actuator, there are two flimsy prongs that contact the track that sends feedback to the programmer about position, my motor had gone past maximum travel and bent those contacts out of position. I bent them back re-installed and rebooted programmer by pulling a/c plug with engine RUNNING, still didnt fix, removed and bent the prongs some more, rebooted, now it SEEMS to be fixed after 3 days of testing and driving. Hope this helps someone in the future. On the same note, I was never able to get the proper readings with my DVM from the blend door as stated in the FSM, dont know if it was me or the book. It said reading should be 7.7 + -500 at full cold and something like 1.7 + -500 full hot (not +/- but PLUS then minus 500).

 

[helphos]

How did you get to the blend door? I think my door is fried, but getting to it to remove it looks ....challenging.

Any advice?

Thanks!

 

[Corvette95]

pull the lower trim panel, then turn yourself upside down with the seat bottom out and take a 5.5mm socket and they are almost hand tight, getting it out is easy....lining the blend door motor up with the blend door motor adapter getting it back in well....no to so easy. any questions feel free to ask.

 

[helphos]

pull the lower trim panel, then turn yourself upside down with the seat bottom out and take a 5.5mm socket and they are almost hand tight, getting it out is easy....lining the blend door motor up with the blend door motor adapter getting it back in well....no to so easy. any questions feel free to ask.

Thanks! I'll give it a try. I'm hoping that when I get the motor replaced all will be well.... :eyerole

 

[Corvette95]

Little tip, set your temperature to 90 BEFORE you pull then blend motor.

 

[helphos]

Blen-Dor

Little tip, set your temperature to 90 BEFORE you pull then blend motor.

Thanks! I'll need all the help I can get. I took off the trim panel before and took pictures to get an idea of where the blend door was, but couldn't see anything. So I'll take the whole passenger seat out and plan to spend some quality time down there with a 5.5 mm socket wrench and a head mounted flashlight. I'll turn the heat to 90, but I may need to plug the replacment into the power plug before installing to get the new motor to align itself to the same angle as the old motor.
we'll see.
Stay tuned!