Air stuck on defrost

[Red Rider]

Look at this link. It is the only reset that worked for me. http://www.tahoeyukonforum.com/forum...ad.php?t=66001

this post also describes fixing rear heat issue.

There are a bunch of crazy ass theories on resetting out there including one i found where they guy insisted that you had to take the car and drive no less the 45 MPH in order to complete the reset... I know engineers can be lunkheads but come on! Also, the pulling the fuse theory is crazy since there are about half a dozen AC fuses.

Re. actuators, never knew what they meant by 'make sure it can't move'. It tried moving mine without forcing and it does not budge most likely due to gearing. Whatever you do, make sure they are installed prior to resetting otherwise you will have to center them manually (mistake i made.)

 

[94SupraTT]

Look at this link. It is the only reset that worked for me. http://www.tahoeyukonforum.com/forum...ad.php?t=66001

this post also describes fixing rear heat issue.

There are a bunch of crazy ass theories on resetting out there including one i found where they guy insisted that you had to take the car and drive no less the 45 MPH in order to complete the reset... I know engineers can be lunkheads but come on! Also, the pulling the fuse theory is crazy since there are about half a dozen AC fuses.

Re. actuators, never knew what they meant by 'make sure it can't move'. It tried moving mine without forcing and it does not budge most likely due to gearing. Whatever you do, make sure they are installed prior to resetting otherwise you will have to center them manually (mistake i made.)

So the process below should work?

1. Disconnect the battery for about a minute.
2. Reconnect battery
3. Turn the ignition to the ON position for at 1-2 minutes. This is the ON position or first position, NOT the RUN position or second position (I made this mistake). On the ON position, the HVAC system should not turn on. So it does not matter if you left HVAC system on front or rear.
4. Turn the ignition to the OFF position for at least 10 seconds. Key can stay in the ignition.
5. Start the engine and confirm the actuators are working correctly by turning the climate knob from cold to hot and from low air, mixed, and high.
6. Have yourself a nice cold beer while the wife praises your status as mechanical genius. (This last step is critical so don't skip it!)

 

[Red Rider]

Yeah. worked for me. I tried everything. fuse thing did not work for me. But that actually did it. Some of the other right ups was not very clear as to what position to turn key to. If you do it properly, HVAC does not kick on so it should not matter if you have it on or not.

Let us know how it turns out. But you may need to replace the controller if it does not work.

 

[94SupraTT]

Yeah. worked for me. I tried everything. fuse thing did not work for me. But that actually did it. Some of the other right ups was not very clear as to what position to turn key to. If you do it properly, HVAC does not kick on so it should not matter if you have it on or not.

Let us know how it turns out. But you may need to replace the controller if it does not work.

I did the procedure this morning however I had the battery off for 3 minutes. It failed. I'll try again tonight.

 

[Red Rider]

hummm. that should have worked. more is better.

Make sure you turn key to the correct position. First click i believe.

 

[tsuintx]

Make sure you turn the key to the first position only. That's pretty much the only thing you need to pay attention to.

 

[tsuintx]

Okay... Guess I could piggyback on this thread with my similar issue.

Earlier my 03 w/digital AC controls had an issue where every time I start the truck you would hear these 6-7 loud thumps from the dash and the air would default to defrost, regardless what setting was chosen on the control unit.

Faulty actuator, right? Easy as a pie, right? Nope, not so much, of course...

Changed the actuator above the gas pedal, did the reset according to Red Rider's instructions. No more thumping noise, but now the air is blowing only through the dash vents, regardless of the direction chosen on the control unit. WTF???

So... What's next? Any ideas are greatly appreciated. Is the new actuator bad or did I mess up my installation somehow? Or is the whole damn flapper thing now broken, or something...? Not really looking forward to getting underneath there again, but oh well...

 

[Red Rider]

Hey tsuintx,

the actuators were actually installed when you did the calibration? I have not yet (hopefully will never) messed with the front of the truck, but I would imagine it is similar to rear.

Did you try doing a second calibration? the first time i did mine, only one of the actuators were being controlled. Then i swapped actuators around, and it started working after a second calibration. I do not know why this would make a lick of difference, but somehow it did. Maybe i simply had not done a proper connection the one actuator?

I would unplug and reconnect all your devices again (actuators and controllers). In fact, plug them in and unplug them a few times. that should clean the contacts. Then try another recalibration.

 

[tsuintx]

Yup, everything was buttoned up when I did the calibration.

The only actuator I changed was the one above the gas pedal. I have done the calibration now twice, but to no avail. I even tried one of the other methods (removing the HVAC fuse etc.), but still nothing but dash vents.

Guess I'll just try again. Not holding my breath, though...

 

[tsuintx]

Tried several methods this afternoon and no change. Unplugged the actuator a few times etc. etc.

One thing I did notice is that during one of the calibrations (forgot which one...) the air actually did change direction to defrost but not to the floor. But in the end it went back to the dash vents.

I starting to think that the new actuator is bad, but what the hell do I know. Wouldn't really like to spend another 50 bucks, or what ever, to find out that it's actually something else, but I guess I'm running out of options here...