Hopefully someone gets the BSG Reference.

So when I maxed out the fan speed on my auto HVAC in my 09 Tahoe LTZ, it sounds as if the fan is speeding up, slowing down, speeding up, slowing down, speeding up, slowing down..

turns out... it's the 'mix' setting. Whatever device actually physically moves to send air to the dash or your feet is causing this.

when I put it on dash, everything seems fine. When I put it to mid, it does it, when I put it to feet, I still get airflow out of the dash vents....

UGH! GM quality in action...

I have the FSM at home, but didn't know if you guys knew what parts may have failed?

It seems to have a hard time adjusting between dash and feet... it's slow to react and won't physically hold the position...

where do I look? Do I have to rip out the whole dash?

 

(raising my hand to the BSG reference )
You might try the relearn procedure as a place to start...
pull the HVAC fuse for 10 seconds, start the vehicle and let HVAC do its relearn for 1 full minute (really 40 seconds) don't make any adjustments during that time..

 

The HVAC has a learn procedure?!

So pull the fuse, engine on. wait 1 min, then put fuse in?

is this fuse powered while the truck is off?

If not, then isn't turning the vehicle off the same thing?

Should I just pull the battery for 10 min and let the truck sit?

I did notice a weird behavior, that I don't know if it's normal.

with the HVAC OFF, i pushed the temp down button, it lit up, changed the temp, then screen went blank again.

tried again, same thing. (is this normal)?

when I push the fan adjust or the on or auto button, it turns on fine.

 

1. Engine off, Pull HVAC fuse, wait 10 seconds re install HVAC fuse (under hood fuse box)
2. Start engine, HVAC system will be on and the system will be in a relearn mode, Do Not make any adjustments to system for a full 1 minute while doors calibrate.( you can hear the doors moving)
3. After full 1 minute calibration should be complete and system operation can be verified...

 

thanks!

is this out of the FSM?

Seems simple enough, after I replace a boat raw water pump tonight I'll give it a shot.

 

Yup from the FSM here is the full text
https://chevroletforum.com/forum/tah...bration-55521/

 

printed it out!

you the man!

what is a DTC?

According to the Manual it's fuse 39 under the hood.

"39 Climate Controls (Battery)"

 

if the re-learn doesn't work...

is this what I'd most likely need?


2003-2010 Chevrolet Tahoe HVAC Floor Mode Door Actuator - Climate Control - Standard Motor Products 03-10 Tahoe HVAC Floor Mode Door Actuator - 3734-05209114 - PartsGeek

 

Now it's stuck on defrost, even when I say I want vent / floor... FML. I have a 200 mile drive coming up and will need my A/C.

I reset it again, and am going to leave it until I can take it somewhere... I'm way to busy to even think about fixing this right now..