Rear HVAC System - Nothing Working

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Sardonic

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First off, nice forum you all have going here. The rear HVAC system in my 2002 z71 is completely shot; the rear controls will not work on any settings at all (speed and/or temperature).

Should I replace the rear blower motor OR should I first suspect something different? If I need to replace the blower motor, can anyone suggest a good DIY guide? I'd like to knock it out myself if at all possible.

Thank you in advance for any assistance.

BTW, I'm not getting any OBDII codes either...
 

chrias

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Remove the passenger side D pillar trim (in the corner) and check the ground bolt. The bolt may have worked it's way loose.
 

Sardonic

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well the lights on the rear control panel are still lighting up at night, but i'll give that a shot anyhow...

thanks for the suggestion!
 

chrias

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They will still light up because the light doesn't draw that much power whereas the HVAC does so it won't kick in. I had the same problem in my 2000 NBS Suburban.

My rear wiper would work but if I turned on the rear defroster the wipers would stop. I found that they all tied into the same ground.

I ripped out a lot of trim pieces to track down my problem and I found it by accident when I saw sparks flying when I pulled on some wires. Turned out it was a loose nut on the ground. lol
 
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Sardonic

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i've never popped off that panel before, but i've heard there's four bolts to remove. would you happen to have any pics of exactly where the ground wire is located? i'd hate to f something up even worse...LOL.
 

chrias

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That panel should just pop right out. There are no screws or bolts holding it. Unfortunately I have no pics but the ground stud is right behind that panel.
 

Holikz

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I have the exactly same problem...I'm gonna check the suggestions mention and i'll try to take pics too....nope nothing worked...
 
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Holikz

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rear a/c not working

Does anyone know if the 05 tahoe LS have 2 separate blower resistor, one for the front and the other for the rear a/c. My rear a/c turn on at all however the lights on the console do work. Anyone have any clue what could be?
 

tekkitan

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I am getting zero air out of my rear HVAC as well. I am going to check this bolt, hopefully it's something small like that. One thing I notice is the center console controls in the rear, if I hit the HVAC power button, it says off. No matter how many times I press it or any of the other buttons I press, it just says OFF in green letters then goes blank after a couple seconds. Not sure if this is what everyone else is experiencing?

BTW, I had the front air running, not sure if this matters or not.
 

calipag

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I am having the same problem in my 02. At first the blower would work every now and then and now I have no blower to the rear of the truck at all. The front A/C and heater work fine, I have no rear fan from either control. I also am going to check the ground stud and from there check the blower motor. I'll let you know how this goes and I'll try to take some pictures.
 

Holikz

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I didn't see any ground bolt on the side pillar after I took it off, just wires running to the top center console....
 

JennaBear

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I had to take my Tahoe to the dealer to get my rear module replaced. There was a TSB out that I pulled up for them, they didnt even know about it. I believe the module was under the passenger side dash.

It is very common for a BCM code B0229 to occur on these vehicles which would result in the exact symptoms you are experiencing. An AutoZone type tool would not show this code.
 
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calipag

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TSB#

I found the TSB #01428B that you mentioned but I can not find details on how to fix the problem. I really didn't want to pay the dealer, has anyone done this?
 

chrias

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I didn't see any ground bolt on the side pillar after I took it off, just wires running to the top center console....

The bolt should be located behind the D pillar trim panel which is the very back corner on the passenger side. If I remember correctly you have to unscrew the cargo net holder knob, pull the very top trim off and then pull the D pillar trim. The stud should be near where the upper and lower trim panel meets.

Mind you, I have a 2000 NBS Suburban so the stud location may have moved in the 03 and newer. I know it's the same in the 00-02 Tahoe. This ground stud tends to loosen the nut over time from all the vibrations.

As for the TSB I never heard about it and I don't know what years it applies to.
 

Holikz

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Anyone have or can take pictures because im very new to the tahoe....
 

calipag

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I have photos.

I'm just having trouble posting them. I took everything apart and had power to the fan but the fan was still not working. I removed the fan and bench tested it and it worked. I reinstalled the fan motor and wouldn't you know it the darn thing is working now. I check the ground stud and it was not loose. I have no idea but with the temps in the low 100's the kids are happy so I'm happy. E-mail me I have a whole procedure of what I did with pictures and I'll send it to you. It took me about a half hour and the only tools you need are a 7mm socket and socket wench and a pair of pliers, plus the test light.
 

Holikz

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I'm just having trouble posting them. I took everything apart and had power to the fan but the fan was still not working. I removed the fan and bench tested it and it worked. I reinstalled the fan motor and wouldn't you know it the darn thing is working now. I check the ground stud and it was not loose. I have no idea but with the temps in the low 100's the kids are happy so I'm happy. E-mail me I have a whole procedure of what I did with pictures and I'll send it to you. It took me about a half hour and the only tools you need are a 7mm socket and socket wench and a pair of pliers, plus the test light.

That's awesome!!! Can you please forward the pictures, I'll send you a PM right now...
 

Holikz

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That's awesome!!! Can you please forward the pictures, I'll send you a PM right now...

Here's what I found out about my resistor...

this is the blower motor resistor .
http://cid-f523587822ea50ab.skydrive.live.com/self.aspx/Public/P6231010.JPG

Here's the other side of it..
http://cid-f523587822ea50ab.skydrive.live.com/self.aspx/Public/P6231012.JPG

Here, I tested to see if I had current from the main cable...which states that my motor resistor is bad and need to replace it asap...
http://cid-f523587822ea50ab.skydrive.live.com/self.aspx/Public/P6231013.JPG


Does anyone know where to order one but not charge a leg and arm?
 

tekkitan

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Here's what I found out about my resistor...

this is the blower motor resistor .
http://cid-f523587822ea50ab.skydrive.live.com/self.aspx/Public/P6231010.JPG

Here's the other side of it..
http://cid-f523587822ea50ab.skydrive.live.com/self.aspx/Public/P6231012.JPG

Here, I tested to see if I had current from the main cable...which states that my motor resistor is bad and need to replace it asap...
http://cid-f523587822ea50ab.skydrive.live.com/self.aspx/Public/P6231013.JPG


Does anyone know where to order one but not charge a leg and arm?

Couldn't it also mean that the blower motor is bad itself and the resistor could be fine? Did you test the blower?
 
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