What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[pwtr02ss]

I gave them a neck choke shake and they did not to seem to have any play.

I mention this because Steph's old escape had a rattle. I replaced the full strut assemblies and new shocks. Still had a rattle. Replaced the sway bar links and it went away. They were the style that has like a ball joint on each end. They felt tight and fine, but were worn. Prob not the problem but it's one more thing to check

 

[Doubeleive]

I just took a look at the diagrams, yeah it's basically a completely different hvac unit in the hybrids. there's it's own 4 pages of diagrams just for it. looks like it might have one more temp sensor and a few more control outputs for extra electric water pumps, 3 speed cooling fans and the electric ac compressor gets a pwm speed control for the compressor rpm. plus a few more odds and ends.

I'll park it in the shade one day with the windows down and let all the Temps equalize. see if I can find one that's off compared to the rest. wouldn't surprise me, but it also wouldn't surprise me if they just did a bad job program it haha. to focused on run time in auto stop vs idling. I have in the past noticed the ac rpm is much lower when stopped than it is when rolling which I thought was weird at the time, I thought maybe trying to mimic a engine driven compressor but other electric compressors I've since looked at data from don't do that.. they adjust speed by pressures needed.

maybe another side effect of gm basically putting a 90s technology nickel metal hydride prius battery in a full size suv and then struggling to make it last 8 years. still feel that was down fall of this truck. if they would have used better in house battery development going on at the same thing frame, these would sill be a thing and getting 30mpg around town.

/rant

you shouldn't have to do that, in the tech2 there is a function to check the sensors/actuators and it just shows "actual" VS "commanded" the outside temp doesn't matter
it goes by what is being commanded and what it is reading inside. I mean I guess if it's -40 out and you are trying to get a halfway decent reading it could throw it off I guess.
windows should be closed because it is reading the inside "controled" environment, rolling the windows down is going to throw another variable in.
the "auto" function reads data off of the headliner and duct sensors, so that's what you should be monitoring once you have established that the actuators are working properly.
there are several small "thermistors" inside the duct's in various locations but one of those being bad is likely rare but easily tested with a blow drier and ohm meter.
more of a PITA to find those than anything, your headliner sensors are going to be the most problematic they have a little fan inside and get worn/dirty.
I would set it for like 77 and then let it get all warmed up with the windows up (for like 15 minutes of driving at least) and then go thru with the tech2 and check each one actual/commanded.

 

[Grady_Wilson]

my other cars with auto I may adjust 2 or 3 degrees up or down depending on summer and winner. but this yukon? can't do it. the auto programing is just awful for me. when I got the truck the buttons looked brand new. not a week later completely worn off. it's just never the right temp. or blowing super loud for nothing.

maybe it's my truck? the Temps from side to side basically do nothing either. you can have a 10deg difference in temp and not tell a single difference. plus I gotta hit recirculate ever time. if I forget, not 5 mins into a drive I got some no cat having Ford work truck stinking me out and then it takes forever to get the air out.

these are all things I have zero problems with in any other vehicle I drive. even older or newer gm auto systems.

could also be we get big temp swings here, it can be 50 on the way to work and 115 with a inside temp of 160 on the way home. but still, my other cars handle it just fine.

I picked up my Yukon with 113k miles on the clock and the only HVAC button that had any wear was the power button.
Mine seems to work OK, but not as nicely as the auto climate controls in my 2017 Kia Optima.
My Optima is truly 'set it and forget it' year round.
The Optima seems to be pretty intelligent about everything going on in the car, if the fan is blowing high enough that it is loud because you just started the car and it's working to get to set temp, and the phone rings, it will automatically lower the fan speed so you can hear the call better.

 

[gooffeyguy]

I picked up my Yukon with 113k miles on the clock and the only HVAC button that had any wear was the power button.
Mine seems to work OK, but not as nicely as the auto climate controls in my 2017 Kia Optima.
My Optima is truly 'set it and forget it' year round.
The Optima seems to be pretty intelligent about everything going on in the car, if the fan is blowing high enough that it is loud because you just started the car and it's working to get to set temp, and the phone rings, it will automatically lower the fan speed so you can hear the call better.

My 2012 Denali does that, lowers the HVAC blower speed when on a call.

Speaking of HVAC buttons, the 2011 Denali I had, had worn buttons and there were those stickers over them when I bought it in 2018. the 2012 that I bought a few months later after the 2011 was totaled had perfectly fine (like new) HVAC buttons and still does. I don't know if the control unit was ever replaced before I bought it from the Buick/GMC dealer or not. I'm thinking not because it was only ~6 years old when I bought it

 

[Doubeleive]

auto works fine here in cali for fall/winter, but once it warms up it's a no go, it can't keep the temperature cool in the summer even with a 100% perfectly working system unless you are on a long drive and it's had time to cool the interior first, I just leave it on manual 60 98% of the time
beside's it's nice to step into 60 degrees from 100 anytime otherwise

 

[89Suburban]

I think I finally found it brothers.

 

[89Suburban]

Have you replaced the sway bar links in the back?

I think I finally found it brothers.

tag rattle

 

[89Suburban]

Gd dman it

 

[Doubeleive]

Gd dman it

ZIP TIE IT, done

 

[iamdub]

ZIP TIE IT, done

NO!!! THE PROPER WAY IS TO RE-ROUTE THE CABLES OVER THE SWAY BAR!!!!11111!!!!ELEVEN!!!!