First, I would like to thank everyone that created this site and the "other" one. Guys like me would be lost without you. I have learned a lot about my Trailblazer from reading here and the "other" site. I do apologize if I have posted this in the wrong place. I did a search and could not find an actual topic concerning my questions. I have a 2002 Trailblazer LT EXT 4x4. I need to replace the actuator located in the center console. I read somewhere else that if that actuator is damaged or fails it will cause the other (I am assuming rear) actuators to reset to default and stay there. Is this true? Once I switch the heat/ac controls to the rear panel nothing works for the rear. No roof to floor control, no heat/ac control, and no fan speed control. While in front control mode, I can only control the fan speed from the front center console switch, but nothing else. So far I have had to manually remove the rear panel and "lock" the actuator doors in place to switch between heat and/or ac and for roof to floor. The actuators look to be in perfect condition as well. Could the center console actuator be causing this problem alone or should I go ahead and plan for new rear control unit (3 knob - manual controls) as well?
Center Console Actuator + Rear HVAC Controls
- Thread starter skidmore
- Start date
neelskit
Member
- Dec 7, 2011
- 69
skidmore said:
As far as I know, if you have an EXT, there are no actuators in the center console. The actuator you are referring to applies only to the short wheelbase models.
skidmore said:
When you have the front control switch set to 1, 2, or 3, the rear mode (floor/ceiling/blend) is controlled by the front HVAC control panel under the radio. The rear system will mimic whatever the front system is set to. The rear air temp is then also controlled by the front HVAC control panel- it will mimic the passenger temp "slider" control. Does your system work this way when set to front control?
skidmore said:
Did you unplug the actuators before forcing them to a new position?
Have you tried pulling the rear HVAC fuse for a few minutes to "reset" the system?
Thank you for your quick response! There is in fact an actuator in the center console. It was making a grinding sound and it took me forever to find where it was coming from. Once I had the console apart I could see that the actuator was trying to work but it looked as though the gears were stripped and would not turn. I wedged the vent door open so that it would let air through. LOL, and yes, I do in fact have an EXT. Third row seats and all, hahaha.
My system is suppose to work with the rear mimicking the passenger side front controls but it does not do so. If I could find a way to make it work that way then I wouldn't worry too much about the rear HVAC controls working properly and would just use the front controls. Considering what I have read, I wasn't certain if the actuator or the rear control panel was the fault of my problems or in fact maybe both are at fault.
Yes I did unplug the actuators before changing mode door positions. I actually removed the actuators, Opened the cover on them very gently, slightly raised one gear to allow me to move the shaft into the needed position and then re-installed. I haven't done this for the heat/ac mode as of yet but I am in need of rear heat now that it is winter here so I must do something to get some heat in the back. I don't mind the cold weather but my kids don't care much for it. I have in fact removed the fuses in an attempt to reset the actuators. I even tried to battery disconnect steps which I located on the TV site a while back.
My system is suppose to work with the rear mimicking the passenger side front controls but it does not do so. If I could find a way to make it work that way then I wouldn't worry too much about the rear HVAC controls working properly and would just use the front controls. Considering what I have read, I wasn't certain if the actuator or the rear control panel was the fault of my problems or in fact maybe both are at fault.
Yes I did unplug the actuators before changing mode door positions. I actually removed the actuators, Opened the cover on them very gently, slightly raised one gear to allow me to move the shaft into the needed position and then re-installed. I haven't done this for the heat/ac mode as of yet but I am in need of rear heat now that it is winter here so I must do something to get some heat in the back. I don't mind the cold weather but my kids don't care much for it. I have in fact removed the fuses in an attempt to reset the actuators. I even tried to battery disconnect steps which I located on the TV site a while back.
neelskit
Member
- Dec 7, 2011
- 69
skidmore said:
I stand corrected!!!! This actuator controls airflow for the middle row floor vents. As far as I can tell, it "piggy-backs" off the front system, but the actuator is controlled by the Auxiliary HVAC Module.
skidmore said:
Either you have loose electrical connections at the Auxiliary HVAC Module, or it is bad.
skidmore said:
It looks like everything in the rear case is good. Remove the Auxiliary HVAC Module from the center console and check the electrical connections. If everything checks out, you will need to replace the module. You should be able to find a used one reasonably. Once you have replaced the module, verify that ALL actuator's electrical connections are connected. Turn the ignition key to RUN, wait 40 seconds for the Auxiliary HVAC Module to calibrate the actuators. You may need to also replace the Console Actuator- see how it behaves with a working module.
@neelskit - Thank you very much for your help! I will go ahead and plan on replacing both actuator and control module. I did have the module out and connections looked good, so the module must be bad. A friend of mine also heard a crackling sound coming from it while having his ear close to it when I switched to rear controls and I figured it was not suppose to do that. 
Hopefully I can find a used one that works. Once again, thank you.
Hopefully I can find a used one that works. Once again, thank you.neelskit said:FYI- You may only need the Control Module, unless the actuator physically looks trashed.
You're Welcome! Be sure to let us know the outcome!
The actuator is trashed. I will be sure to post back later, but it may be after Christmas. Big family + lots of presents = no extra money.
I wish everyone here a Merry Christmas in case I don't make it back before then.
I just wanted to give an update to the problem I was having. I ordered a used rear climate control module from eBay. I paid $43 shipping and all (vs. over $200 new from dealer). I received it this evening and installed it. All is working well in the rear of the TB now . My old control module was clearly defective. I took my old one apart and saw that the potentiometers inside were broken into pieces for some reason, possibly previous owners and kids kicking the knobs, who knows for sure. I have not fixed the actuator in the center console yet and seeing that it isn't really a big deal since it only controls the two small floor vents for the middle row, and it does NOT cause anything else to stop working, I may never replace it. I'm just happy that all rear controls are now doing what they are suppose to do. A big thank you goes out to neelskit for helping me with this issue. I'll be sure to update if I ever decide to tear into that center console actuator. For now my next projects are round tube nerf step bars, driver side tail light lens, rear window regulator w/ motor, window switch, rear shocks, tail gate glass shocks, whatever is wrong with the E-brake, and that horrible scrubbing sound coming from the dust and water shields that are rubbing on the rotors 
.
. My old control module was clearly defective. I took my old one apart and saw that the potentiometers inside were broken into pieces for some reason, possibly previous owners and kids kicking the knobs, who knows for sure. I have not fixed the actuator in the center console yet and seeing that it isn't really a big deal since it only controls the two small floor vents for the middle row, and it does NOT cause anything else to stop working, I may never replace it. I'm just happy that all rear controls are now doing what they are suppose to do. A big thank you goes out to neelskit for helping me with this issue. I'll be sure to update if I ever decide to tear into that center console actuator. For now my next projects are round tube nerf step bars, driver side tail light lens, rear window regulator w/ motor, window switch, rear shocks, tail gate glass shocks, whatever is wrong with the E-brake, and that horrible scrubbing sound coming from the dust and water shields that are rubbing on the rotors .