2005 Yukon: The dreaded blend door question(s) - Loud behind glove box

[LJSeinfeld]

I've been searching, trying things for days/weeks-- Super common search terms, so a lot of false positives. Sorry if it's been asked/answered before.

I'm having an issue where things are working fine hvac-wise, and then after some time (30-45 minutes-ish) I lose nearly all flow to any vents (dash, defrost, floor) and I can hear louder than normal air noise coming from, what sounds like, behind the glove box. If I turn the HVAC system off for a few minutes and turn it back on, it seemingly returns to normal for x-amount of time.

Mode door actuator (driver's side) has been recently replaced and is working.

I think there are like 3 other actuator motors to look at, trying to determine which one is likely the culprit. This is with the dual zone automatic climate control, btw.

Thanks for any insight you can provide.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

@swathdiver ; @OR VietVet may be able to provide you with some suggestions and perspectives.

 

[OR VietVet]

Welcome to your first post at the forum.

I have no idea why it works SOMETIMES but some here have removed their battery cables, both of them, let sit for about a minute, then touch the cable ends together for 5-10 seconds and then reinstall at the battery. If this does not work, it does sound like an actuator problem possibly. Others will chime in with more info.

 

[LJSeinfeld]

Welcome to your first post at the forum.

I have no idea why it works SOMETIMES but some here have removed their battery cables, both of them, let sit for about a minute, then touch the cable ends together for 5-10 seconds and then reinstall at the battery. If this does not work, it does sound like an actuator problem possibly. Others will chime in with more info.

Thanks -- I have done the 'normal' reset procedure by pulling the HVAC fuse for like a minute, reinstalling it and letting the unit move the motors. The weird part is, I start out fine and then like 40 minutes later, loud air noise from the glovebox area and crummy flow to any ductwork. Issue happens in winter/with heat as well.

 

[OR VietVet]

That flow change tyically means an actuator problem.

 

[Fless]

A good bidirectional scanner should be able to look at live data of the HVAC controls and actuators. For each actuator, what position is commanded vs. what the actuator is actually doing.

 

[swathdiver]

I've been searching, trying things for days/weeks-- Super common search terms, so a lot of false positives. Sorry if it's been asked/answered before.

I'm having an issue where things are working fine hvac-wise, and then after some time (30-45 minutes-ish) I lose nearly all flow to any vents (dash, defrost, floor) and I can hear louder than normal air noise coming from, what sounds like, behind the glove box. If I turn the HVAC system off for a few minutes and turn it back on, it seemingly returns to normal for x-amount of time.

Mode door actuator (driver's side) has been recently replaced and is working.

I think there are like 3 other actuator motors to look at, trying to determine which one is likely the culprit. This is with the dual zone automatic climate control, btw.

Thanks for any insight you can provide.

I'm presently experiencing the same thing with my 2009. I've changed all the actuators by now and have calibrated them several times with my Tech-2 and none of them show the door positions out of spec. The blower motor is going but little air is coming out the vents. I do have a cabin filter and have been trying to get a helper to pull it out to rule out a blockage. Yesterday however, lots of air was coming out the vents, more than normal. I thought my daughter pulled the cabin filter but she said no.

I'm wondering if the foam on the recirc door is wearing down allowing air to bleed off outside. When the weather cools I plan to pull the airbag and watch the door position move and see if they seal the fresh air (recirc) door. I really don't see anything in the troubleshooting guide other than these things to check. Sure hope a squirrel didn't store a bunch of nuts in there for the winter!

 

[latvius]

I've been searching, trying things for days/weeks-- Super common search terms, so a lot of false positives. Sorry if it's been asked/answered before.

I'm having an issue where things are working fine hvac-wise, and then after some time (30-45 minutes-ish) I lose nearly all flow to any vents (dash, defrost, floor) and I can hear louder than normal air noise coming from, what sounds like, behind the glove box. If I turn the HVAC system off for a few minutes and turn it back on, it seemingly returns to normal for x-amount of time.

Mode door actuator (driver's side) has been recently replaced and is working.

I think there are like 3 other actuator motors to look at, trying to determine which one is likely the culprit. This is with the dual zone automatic climate control, btw.

Thanks for any insight you can provide.

The other actuators are an upper and lower blend door (assuming you have dual zone) the blend door handles hot/cold. The one behind the glove box is the air recirculation door. When you use heat it should pull air from the outside and when you have cold on and press the recirc button the actuator should move the recirc door so you no longer draw air from the outside which makes the air blow harder out the vents.

So it sounds like your recirc actuator and/or door is the problem. The door could be broken.

 

[LJSeinfeld]

I'm presently experiencing the same thing with my 2009. I've changed all the actuators by now and have calibrated them several times with my Tech-2 and none of them show the door positions out of spec. The blower motor is going but little air is coming out the vents. I do have a cabin filter and have been trying to get a helper to pull it out to rule out a blockage. Yesterday however, lots of air was coming out the vents, more than normal. I thought my daughter pulled the cabin filter but she said no.

I'm wondering if the foam on the recirc door is wearing down allowing air to bleed off outside. When the weather cools I plan to pull the airbag and watch the door position move and see if they seal the fresh air (recirc) door. I really don't see anything in the troubleshooting guide other than these things to check. Sure hope a squirrel didn't store a bunch of nuts in there for the winter!

The weird part is that it works fine for x amount of time. Assume some door/damper is moving somewhere and then staying in some halfway position? Hoping not to have to pull the dash, but I think that's what's next..

 

[LJSeinfeld]

The other actuators are an upper and lower blend door (assuming you have dual zone) the blend door handles hot/cold. The one behind the glove box is the air recirculation door. When you use heat it should pull air from the outside and when you have cold on and press the recirc button the actuator should move the recirc door so you no longer draw air from the outside which makes the air blow harder out the vents.

So it sounds like your recirc actuator and/or door is the problem. The door could be broken.

So this totally feels to me like something isn't where it needs to be on way or the other and air is just 'loosely' blowing around in, what appears to be, the area of the glove box