2004 rear fan

[Rivelite]

Part of the reason that actuator door fails in the rear HVAC unit is the plastic gears over time wear and the door overextends itself and gets stuck when it moves moves from ac to heat. The part is easy to replace but if you do not do either the calibration procedure or have it dove via Tech2, then the door will "overextended" again because the sensor position is not calibrated and will try to push the door further than is should go again. This is how my new actuator broke again right after I installed it. I was in a pinch and needed to sort it out fast as I was leaving for a roundtrip the next night. If you remove the actuator from the HVAC unit you can see the knob that it rotates to control the ac/heat. I just flipped the knob to heat and opened the actuator with a small flat head screwdriver and pulled out 2 of the plastic gears and positioned them to align with the knob to the heat position. Just put the plastic gears back together, snap the actuator together and stick it back on the HVAC unit itself. I did not plug it in so only the heat blows at this setting. This took all of 2 minutes to do and fast-forward 3 years later and I still just manually flip the gears instead of buying a new actuator. It takes me 10 minutes ever year to pull the trim, open the actuator and flip the gears towards AC when I need it. Yeah, I know it is not the proper fix and I lose the ability to adjust the heat/ac mix in the back via the controls but it is free and quick. Maybe one day I will get a new actuator and have it programmed properly but this I how I do it for now... Good Luck!

 

[Gnarley]

Just write down the part number on that rear blower resistor and take it to the auto parts store or order it online and/or take the old resistor with you to match it up at the autoparts store
99.99999% chance it is just the resistor gone bad, no sense in complicating it.

The blower resumed normal operation, I DK why??? At issue now is the rear blend controls.

 

[Gnarley]

Part of the reason that actuator door fails in the rear HVAC unit is the plastic gears over time wear and the door overextends itself and gets stuck when it moves moves from ac to heat. The part is easy to replace but if you do not do either the calibration procedure or have it dove via Tech2, then the door will "overextended" again because the sensor position is not calibrated and will try to push the door further than is should go again. This is how my new actuator broke again right after I installed it. I was in a pinch and needed to sort it out fast as I was leaving for a roundtrip the next night. If you remove the actuator from the HVAC unit you can see the knob that it rotates to control the ac/heat. I just flipped the knob to heat and opened the actuator with a small flat head screwdriver and pulled out 2 of the plastic gears and positioned them to align with the knob to the heat position. Just put the plastic gears back together, snap the actuator together and stick it back on the HVAC unit itself. I did not plug it in so only the heat blows at this setting. This took all of 2 minutes to do and fast-forward 3 years later and I still just manually flip the gears instead of buying a new actuator. It takes me 10 minutes ever year to pull the trim, open the actuator and flip the gears towards AC when I need it. Yeah, I know it is not the proper fix and I lose the ability to adjust the heat/ac mix in the back via the controls but it is free and quick. Maybe one day I will get a new actuator and have it programmed properly but this I how I do it for now... Good Luck!

It's not the actuator, I noted this having swapped them and the blend instructions tell either actuator to go full cold. I've removed the cover to the actuator, you can see it in the pictures and I set it to warm after moving the door to the heated position and then putting the gears back into position to hold the door in place. It returns to full cold no matter what I do, so it is not an actuator. It may be a temp sensor or the control module.

 

[Rivelite]

My diagnosis is from working on my 2003 Esky which should be the same. From what I understand the blower motor resistor controls fan speed and the Control module sends the commands to the actuators to move the blend doors. I bought the control module in 2017 (AC Delco 15-73506) and it fixed my problem with the doors not taking the commands for ac/heat ceiling/floor. I just did not calibrate correctly it and it destroyed my new actuator, hence why I just manually change up up now.

 

[Gnarley]

My diagnosis is from working on my 2003 Esky which should be the same. From what I understand the blower motor resistor controls fan speed and the Control module sends the commands to the actuators to move the blend doors. I bought the control module in 2017 (AC Delco 15-73506) and it fixed my problem with the doors not taking the commands for ac/heat ceiling/floor. I just did not calibrate correctly it and it destroyed my new actuator, hence why I just manually change up up now.

Thanks, I considered it may be the control module (AC Delco 15-73506) or even the less expensive ambient air temp sensor. Any idea how much it costs to reprogram a new control module with someone who has a Tech II?

 

[Rocket Man]

Thanks, I considered it may be the control module (AC Delco 15-73506) or even the less expensive ambient air temp sensor. Any idea how much it costs to reprogram a new control module with someone who has a Tech II?

You don’t need to with this year, at least my 02 didn’t need it.

 

[Rivelite]

Thanks, I considered it may be the control module (AC Delco 15-73506) or even the less expensive ambient air temp sensor. Any idea how much it costs to reprogram a new control module with someone who has a Tech II?

All these systems do work together but I am not too sure how a faulty AAT sensor would be the culprit for your specific issues. I am leaning towards the control module. My shop told me they would hook it up to their programmer and make any of the necessary programming assuming it was the control module that I changed that needed to be calibrated and they would bill me for one hour which was 115.00 bucks. That's why I decided to just set the gears in the actuator to align to allow for heat and reinstalled but did not plug it in. In the summer i just pull the panel and align the gears to the AC side and reinstall with out plugging it in. Done and Done.

 

[Gnarley]

All these systems do work together but I am not too sure how a faulty AAT sensor would be the culprit for your specific issues. I am leaning towards the control module. My shop told me they would hook it up to their programmer and make any of the necessary programming assuming it was the control module that I changed that needed to be calibrated and they would bill me for one hour which was 115.00 bucks. That's why I decided to just set the gears in the actuator to align to allow for heat and reinstalled but did not plug it in. In the summer i just pull the panel and align the gears to the AC side and reinstall with out plugging it in. Done and Done.

Maybe for your system but several have suggested that for mine a 2004 You don’t need to with this year, at least my (Rocketman says) 02 didn’t need it.