Suddenly my climate control isn't right

[guy48065]

Just this week my AC is so cold it's intolerable. I've fiddled with the climate control (I have the optional automatic control) and have found that when set to any temp below OUTSIDE temp the AC compressor runs and it blows cold. It's supposed to adjust to INSIDE temp. It always worked a treat set to 74 for the summer. Now it needs to be re-adjusted as outside temps change and it's just weird seeing it set to 85 to get a comfortable temp INside.

I don't know yet if this has also affected the heat settings. It's too warm lately to test that.

Heard of this before? Maybe (I hope) a TSB about it?

Physically where is the cabin temp sensor located?

[Paulaurora]

maybe blend door issue or temp sensor issue

[guy48065]

Well...the blend door does seem to function fine. I change the temp setting and the temperature DOES change immediately.

As for the sensor--it acts like it's monitoring outside temps rather than inside. Does the climate-control unit have a sensor for both? Maybe this is how it behaves when it loses a signal from the inside sensor?

Again--where is the inside sensor?

[tigger]

Jun 19, 2017 10:17:04 GMT -6 guy48065 said:

Again--where is the inside sensor?

[guy48065]

I think I jumped to the wrong conclusion that the climate control seemed sensitive to outside temps rather than inside. Well yesterday we got a break in the recent heat and I actually needed heat in the morning and no AC in the afternoon. I needed to set the control to the same temperature (~85) to toggle between heat & cool. It "doesn't care" whether it's 90 or 60 outside, or what the inside temp is. Looks like the control is running "open loop" due to either bad sensor or bad control unit.

Is there a procedure to test the control unit?

[RCA1186]

Not sure if the 2G uses the same system but I had a similar problem that was solved with a new A/C programmer. Looks like a small PCM and is under the glovebox on a classic. It'd be a gamble though. New...they're pricey, I ran into one for cheap on eBay.

If you have an FSM use the diagnostic flowcharts to pinpoint the problem based off symptoms. That's how I narrowed it down to the programmer.


You might try the blend door re-learn procedure

Jun 14, 2009 9:31:47 GMT -6 oldwino said:

My 02 FSM(believe 01 will be the same) says for the actuator relearn procedure to pull the fuse for the Instrument Panel Control Module and that the fuse must remain out for a minimum of 60 seconds.

[guy48065]

This problem coincides with some work I had done to the system under the hood. I had a leaky hose replaced and the system re-charged. I don't see the connection but maybe I'm missing something that was done outside that could affect the way it works inside?

[Paulaurora]

i think it sounds like blend door going bad but you can try to actuator relearn procedure to pull the fuse for the Instrument Panel Control Module or disconnect the module it self for few min. Then you just put the car to on but dont start the engine and once you put the air on you will hear actuators moving and first it will be cold air then hot then it will cycle to the modes like blow up down etc. But if u have to put 85 to blow cold air that deff actuator issue.

[guy48065]

Paul can you check your post regarding the re-learn process? I'm not going to get hot & cold if it's not running...

[Paulaurora]

well if your car is cold yes you wont get hot its always be cold but if car warmed up u dont need to have engine started to get cold or hot air .

[guy48065]

I googled for the re-learn and there was a line in it that made the dusty old lightbulb light up:
"Do not touch the climate controls during the procedure or performance may be negatively affected."

So I'm thinking what if a small town repair shop knows nothing of this trick, disconnects my battery to work on the AC hose, then monkeys with the settings while verifying his work?

I did the re-learn and now it's fine.