Front Defroster Suddenly Ticks

[l008com]

My Christmas present this year is a broken defroster. When I try to put my front windsheild on defrost, it just started doing this:

What do you make of that?
If I had to guess, I would say a broken fan box and the fix is to fully take the whole dash apart to replace some $3 part?

Please oh PLEASE tell me I'm wrong!

I don't think it ever stops or ever start blowing the bulk of the air out the front defroster. I don't use the front defroster very often, I generally keep the HVAC on auto or on vent & floor combo. Only when theres actually nice on the front window, do I switch it over.

 

[movietvet]

Depending on if you have manual controls or automatic controls, I did not watch the video, you can go to you tube and watch at least 3 videos, of each kind, for doing a reset on the heating-a/c system. I say 3 of each because there are some flakes out there that do not know how to communicate to other people. A friend of mine, had a manual control system and had some clicking noises and I did a reset and has worked fine for 8 months now.

I just listened to the noises. That is louooodah! Metal on metal. Try the reset and see what happens.

 

[l008com]

I don't think its quite as loud in person as it sounds in the video. The phone was closer to the dash when I recorded the audio, than the camera was when i took those random pictures.
In person it does not sound like a metal on metal sound, it definitely sounds like plastic. But still pretty hard for a plastic bang

 

[Mooseman]

Yep, try the reset but I'm putting money on the actuator being DOA. Classic symptom.

Post in thread 'a/c control issues 2005 TB'

Sep 11, 2012

Welcome! This is the new clubhouse for discussing technical issues. Curious how you discovered us, since trailvoy attempts to censor any mention of the couple thousand "disloyal ones".

Anyway, it really takes a GM Tech II tool to take control of the HVAC control module and put each actuator through its paces. If you recently changed or discharged the battery, the lack of voltage to the control module memory forces each actuator through a recalibration process. That process is often stressful to older actuators and they get flaky or die.

Perhaps you've seen my main actuator...

• The_Roadie

 

[movietvet]

Yep, try the reset but I'm putting money on the actuator being DOA. Classic symptom.

Post in thread 'a/c control issues 2005 TB'

Sep 11, 2012

Welcome! This is the new clubhouse for discussing technical issues. Curious how you discovered us, since trailvoy attempts to censor any mention of the couple thousand "disloyal ones".

Anyway, it really takes a GM Tech II tool to take control of the HVAC control module and put each actuator through its paces. If you recently changed or discharged the battery, the lack of voltage to the control module memory forces each actuator through a recalibration process. That process is often stressful to older actuators and they get flaky or die.

Perhaps you've seen my main actuator...

• The_Roadie

Yep. First thought is always the actuator but I was surprised when the reset took care of my friend's 2005 Tahoe with manual controls.

 

[l008com]

So I've been ignoring this all winter but time to revisit and fix.

Here's what I learned. Its actually clicking any time I try to take it OUT of dash-vent mode. Floor and vent is fine, vent only is fine. Any setting with no vent, clicks non stop. INCLUDING shutting the system off entirely!

I did not try any fuse pulling. It was a super cold winter so like I said, I just ignored it. Is it still worth trying that or do the symptoms indicate a definite hardware problem?

I'll probably have time to try the reset process Friday. If it is a hardware problem, what would it be exactly? And how hard is it going to be to fix it?

 

[Mooseman]

Definitely an actuator, likely the floor/dash vent one. If it's clicking, a reset is not likely to fix it but you can try. If it does, it won't be permanent.

 

[l008com]

Ok update time. I FINALLY got around to doing the reset. There were 4 HVAC fuses and I yanked them all, checked my tire pressure all around, then put them back in.

Unfortunately, things are much worse now

It now clicks for a minute or two straight, every single time I turn on the truck.

So, actuator it is? How many actuators are there? What is ACTUALLY happening/failing here? Is this something I can fix by removing the center console but NOT removing the whole dash, hopefully?

 

[Mooseman]

There are 5 actuators:

Post in thread 'a/c control issues 2005 TB'

Sep 11, 2012

Welcome! This is the new clubhouse for discussing technical issues. Curious how you discovered us, since trailvoy attempts to censor any mention of the couple thousand "disloyal ones".

Anyway, it really takes a GM Tech II tool to take control of the HVAC control module and put each actuator through its paces. If you recently changed or discharged the battery, the lack of voltage to the control module memory forces each actuator through a recalibration process. That process is often stressful to older actuators and they get flaky or die.

Perhaps you've seen my main actuator...

• The_Roadie

Try each control individually. For the mode, go from defrost to dash vents for the defrost actuator, then from dash to floor for the floor/dash actuator, then each side temp for those two. Then try the recirc. Hopefully that one is fine as it does require dash removal. Pass side temp actuator requires some cutting of a dash brace located right in front of it.

 

[TJBaker57]

Ok update time. I FINALLY got around to doing the reset. There were 4 HVAC fuses and I yanked them all, checked my tire pressure all around, then put them back in.

Unfortunately, things are much worse now

It now clicks for a minute or two straight, every single time I turn on the truck.

So, actuator it is? How many actuators are there? What is ACTUALLY happening/failing here? Is this something I can fix by removing the center console but NOT removing the whole dash, hopefully?

Personally, I would begin by replacing BOTH the MODE and the DEFROST actuators. These are the two that control where the airflow goes AND they are the easiest to do. They are right next to each other on the drivers side above the area of the accelerator pedal. On my 2002 after the lower dash/footwell covers are dropped there is one plastic air duct that needs to come out to get good access to them.