Blend doors going thump in the night

[largewon62]

I have a 1997 Yukon and the darn front heater blend doors make a thumping noise randomly. Is that normal? The heat rocks!!!

 

[scottg918514]

Mine was clicking then would get stuck and blow all hot (in the summer). Replaced the actuator, all good.

 

[97WhiteYukon]

http://s308.photobucket.com/user/de...C-189AAF2FDE74-1166-000001535A74AC79.mp4.html

Let me know if that link doesn't work, but this is what mine used to sound like. It would thump some times but mostly that whine would start up, getting underneath it I could see the door would open and close. Other than that everything seemed to work normally for the most part. I hope that's not the one your having trouble with its a pain in the ass to get to. This one is under the passenger side near the floor behind the big plastic ducting box I think the heater core is in. Got to remove the dashboard usually. Someone must have got to it before me though, I managed to change it without taking everything apart because the one screw I would never have been able to get to without taking the dash apart was missing. There is 2 more holding it in place so its not going anywhere. If the one making the noise for you is under the driver side near your feet that ones easy to change out.

 

[largewon62]

Thanks for the response. Mine makes a similar noise occasionally, but I blame that noise on my girl eating too much chili.

Seriously, mine does make that same noise and thumps like someone firmly closing a sealed door.....THUD!!!

I thought it may be the dash controller going wacky and randomly opening and closing a door, but there is no difference in the hear or Ac output.

Did replacing that actuator motor fix the issue?

 

[97WhiteYukon]

Mine used to thud sometimes, I think I know what your talking about. I just remember that whining sound would get so annoying. replacing the actuator fixed it completely and instantly. You might want to stick your head down there when it does it just to make sure that's the right one.

 

[Monstar_est87]

Here u go fellas hope this helps... I put up pix in this thread of my adventures...
To possibly skip the headache of removing the dash...
http://www.tahoeyukonforum.com/forum/showthread.php?t=25206&page=8
Just remember do not remove the actuators and test them out... I know it sounds like a good idea but this will throw off the settings... It will over shoot its proper settings and wont blow out correctly wen u put it back on... Meaning wen u adjust the HVAC controls for a the defrost it could possibly blow out the dash or to ur feet... And its such a pain to get the all synced up again... Might even have 2 run 2 the parts store for new actuators... Ask me how I know...

Yea it's doable in two days but it's a shitload of work and it was my first time so it was pretty slow going but I was able to clean it up a ton and replace a lot of old parts and seals. Here a the best pics I could find of all three of the actuator motors.

Heres the mode select motor which you seem to be having trouble with. Its sticking staight out the left side of the HVAC pointing into the steering column. You can probably see it with the whole dash installed and honestly it might be possible to replace it without removing the dash but it'd be close I think. (Its right behind the steering column support structure)


Pic of the very left side of the HVAC

Here is a pic of the temperature control door actuator in the middle of the HVAC facing back toward the cabin. Almost 100% sure this cant be removed without some removal of the dash, its behind a support structure.


Here are the ever elusive pics of the recirculator door actuator. These are the best I had to give you an idea of where it is it. It is actually the only motor that is uncovered and I'm pretty sure with a little wiggle work it can be replaced without removing anything else so it's not too bad despite being tucked way up under the dash.



BTW to whoever thinks their AC is working at 100%, if your truck is as old as mine I can guarantee that it's not. Looking forward to seeing how much more efficient the new clean evaporator is during the hot ass summers down here in florida.

 

[jbuck07]

Subscribed! Mine does the same thing. And....my A/C sucks too! Looks like I may have to take apart my dash. How hard was that??


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[SunlitComet]

You can clean almost all of the evaporator without removing it.

---------- Post added at 01:41 PM ---------- Previous post was at 01:41 PM ----------

Pull out the blower fan and insert hand. You will find it.

 

[jbuck07]

I tried that a while back when I posted on another thread about how bad the air smells. I used a water hose to spray most of that stuff out. I couldn't get my hand in there good enough and I did pull the fan out too. Would I still have to remove the dash to take the coil out? I may have to anyways since it seems like my actuator is going out because of the door flap thing....


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[SunlitComet]

yes as well as discharge, evacuate and recharge your A/C as well as drain your cooling system.