2005 Trailblazer EXT rear blower problems

[triogre]

To start, this is my first time posting anything, so hello everyone. Next, I am sure this question has been asked before, but unfortunately I cannot find my exact situation, so sorry if this is a repeat. I, like many others, am having issues with my blower controls.

The front heat/AC works just fine, there is nothing wrong with that. The rear however, I'm highly annoyed with. It hasn't worked since we got the TB a little over a year ago. The only thing that works is the high setting. No matter what level you put it on, it is always on high. The heat/AC works, but only on high. It also doesn't matter what control I'm using, the one by the front seats or the rear controls, it still has the same effect.

I just changed the blower motor resistor hoping that would be it, but of course it's not.

My question is, what is the next logical thing to check, and where is it located?

Also, there is a random plug not attached to anything near the resistor pack, I was wondering if it's supposed to be connected to anything? The pictures show the plug I'm talking about.

I'm not used to the front/rear climate control type items.


Any help would be greatly appreciated and thank you in advance.

 

[Blckshdw]

The yellow plugs deal with the air bag system I believe...

For your rear HVAC system, you'll want to replace the blower speed control module behind the passenger side cargo panel. I borrowed this pic from Roadie.

 

[The_Roadie]

Welcome!

In the rear, we don't call it a blower resistor because it's really a solid-state (electronic) control, but as long as that's the item you changed, then that can't be the problem. Do you have a voltmeter and some electrical troubleshooting experience and want to dig deeper?

Say, you didn't change the FRONT blower motor resistor pack? That's not at all involved with the rear blower motor speed problem.

The detail that's usually critical to identifying mystery connectors is the wire color on each of the pins. Can you identify the colors involved?

And sometimes a bigger picture view of the location the mystery connector and its harness are in.

Say, that isn't a connector near the front blower behind the glove box, is it? It matches the shape of connector C203 that brings the side impact airbag sensors to the body wiring harness. If it was disconnected, you'd also have a permanent Airbag system warning light on the dash. Do you have this? Any other maintenance history you can share? Or if it's a used vehicle, could a scumbag previous owner have disabled the dash light to fool you into thinking it was a good system.

See if the Airbag warning lilght comes on when you first turn on the ignition during the lamp test time. Consult your owner's manual for the exact position of the light on the gauge cluster.

 

[triogre]

I did replace the resistor in the front under the advice from a knowledgeable guy I know. He, like me, does not have much experience in the HVAC systems that have multiple "zones" I guess you would call it. Turns out, the front resistor that is in it is an obvious replacement, but since I got a good deal through a connection, I'll probably leave the one I put in. By the glove box is where the mystery plug is, and after checking, when I turn the TB on, the airbag light comes on and flashes 5 times then shuts off. The TB also dings 5 times, but I thought that was normal, like it was the door ajar or seat belt warning. I'm thinking now it is linked to the airbag system.

A little history about the car. I bought it from a used car lot here in town (yes, unfortunately I did make that mistake). I already had to replace quite a bit of suspension and steering items on the front end due to the previous owner putting oversized tires and rather large wheel spacers on it. The differential I believe it's called for 4WD had to be replaced as well. I also noticed that the rear door panels had been taken off and several rivets or whatever you call them that hold the panel in place are broken. The only speakers that work are the two front speakers, I haven't investigated that quite yet.

What it looks to me after digging in deeper is that the previous owner tried to "soop" it up and did a terrible job at it.

Anyway, suspension and front end is fixed, regular sized tires are on it, spacers are history. It drives great now. Just the issue with the rear HVAC system.

All in all, I thought most of the issues I saw at the time of purchase were minor (the problems with suspension didn't become apparent till a couple of months after the purchase). The engine runs well and have (knock on wood) had no issues with that.
Luckily, while purchasing the car we purchased the "warranty" that they offered which paid for virtually all of the suspension work. I believe the "warranty" will cover airbag system issues as well, but I'll have to check. The amount the warranty paid on the front end work was more than enough to pay back what we paid for the warranty.

I'll have to find the panel in the back that holds the rear HVAC and take a look at that. Would you happen to know what NAPA would call the "resistor" for the back?

Thanks everyone for the help.

 

[Texan]

Were side impact air bags standard equipment in 2005?

 

[The_Roadie]

I did replace the resistor in the front under the advice from a knowledgeable guy I know.

As you can guess, nobody knows these systems like the volunteers here. For almost ten years and thousands and thousands of posts, the data here and on trailvoy (where we all were until new owners killed the culture) can save you thousands of $$.

He, like me, does not have much experience in the HVAC systems that have multiple "zones" I guess you would call it.

Ummm, checking the forums FIRST would be advisable now you know about us.

Turns out, the front resistor that is in it is an obvious replacement, but since I got a good deal through a connection, I'll probably leave the one I put in.

If the wiring was burned at all, or if you had lost any of the speeds onthe FRONT blower, that was a good call.

By the glove box is where the mystery plug is, and after checking, when I turn the TB on, the airbag light comes on and flashes 5 times then shuts off. The TB also dings 5 times, but I thought that was normal, like it was the door ajar or seat belt warning. I'm thinking now it is linked to the airbag system.

That's right. I think it's all in the Owner's Manual. Did you get cheated out of one of those? There are PDFs on the net that are trivial to locate. Every page is worth reading at least once.

A little history about the car. I bought it from a used car lot here in town (yes, unfortunately I did make that mistake). I already had to replace quite a bit of suspension and steering items on the front end due to the previous owner putting oversized tires and rather large wheel spacers on it.

That's what we ALL do on our sister site offroadtb.com. Wonder if the owner was a member.

The differential I believe it's called for 4WD had to be replaced as well.

Differential is on the driver's side of the oil pan. The transfer case is on the tail end of the transmission, and that is easily killed by neglectful maintenance. Can you check which one you got changed? The fluid change interval for the transfer case is a surprisingly short 50K, and it still have to be changed even if you never use 4WD mode.

I also noticed that the rear door panels had been taken off and several rivets or whatever you call them that hold the panel in place are broken. The only speakers that work are the two front speakers, I haven't investigated that quite yet.

That previous owner sounds like a lazy goof.

What it looks to me after digging in deeper is that the previous owner tried to "soop" it up and did a terrible job at it.

There are careful and proper ways to lift these vehicles. Again, he was a goof.

Anyway, suspension and front end is fixed, regular sized tires are on it, spacers are history.

Those spacers must have been custom, and worth a buck because the GMT360 platform has a unique stud pattern. It you chucked them, there went $100 you might have not known about. What about any spacers in the other suspension parts?

Would you happen to know what NAPA would call the "resistor" for the back?

Print my diagram and take it in. Or buy one on Ebay. They're around $100. Except at a GM dealer, where they could be $200.

 

[triogre]

Thanks for the help. I have the diagram and I'll take it in and ask them. I'll look more into the plug situation. And this TB would be pretty nice to have larger tires on and have it customized a little bit. I didn't throw the spacers away, I got about $100 selling them actually. The way he tried to customize the car was all wrong. It looks like he got midway through it and decided it wasn't worth it, so he got rid of it.

It's a nice TB overall, it's just got some things that need fixed. Don't believe I got the manual, but I'll look it up.

Thanks again for the help. I'll let ya know how fixing it goes.

 

[BRomanJr]

Were side impact air bags standard equipment in 2005?

Went searching and found:
For 2005 the RPO for Side curtain airbags is ASF.

Don't think they were standard.
Check your glovebox door sticker.

 

[C-ya]

Were side impact air bags standard equipment in 2005?

Went searching and found:
For 2005 the RPO for Side curtain airbags is ASF.

Don't think they were standard.
Check your glovebox door sticker.

Not standard, as I don't have them.

 

[Blckshdw]

Were side impact air bags standard equipment in 2005?

Went searching and found:
For 2005 the RPO for Side curtain airbags is ASF.

Don't think they were standard.
Check your glovebox door sticker.

Not standard, as I don't have them.

Me niether....

 

[triogre]

Well, took panel off, figured out the module is behind the whole unit, getting the rest of the unit apart so I can get to it. All other wires look good, checked the fuse and that's good. Haven't fully gotten to the module, but I do see the actuators. Is it possible that one of the actuators could be bad and not the module?

I gotta get ready and head to work right now, so this is a to be continued............lol

 

[The_Roadie]

Bad actuators would click, and fail to control the temp or the airflow direction. The blower motor is separate functionally.

 

[triogre]

Thank you. Gotta wait a few days for the replacement module. In the mean time, I'll try to test the electrical and attempt to fully diagnose it.

 

[triogre]

Ok, I'm working on getting to the control module and having some issues. I have the cargo panel off as well as the metal plate. This might sound like a dumb question, but do you have to take the whole system apart to get to it? I know where it is located, just not sure how exactly to go about getting to it. If you have to take the whole thing apart, is there a way to do it by just removing the plastic housing and leaving the heater core and such in place?

Thanks again

 

[The_Roadie]

I don't have an EXT/XL, but I've read you can loosen some assembly mounting screws and tilt it toward the inside of the cargo compartment.

 

[triogre]

Well I got the module installed and the speeds work correctly now. Now I am looking for one more part. It is number 36 in the diagram on this thread. It's the flap that the temp control actuator uses. I need to see about replacing the actual flap and possibly the actuator. I took the actuator off to ensure that it is functioning properly, but in doing so, the end of the flap broke off into the actuator. I think I can get the part that broke off out, but I cannot find any information or way to search for a replacement flap. I guess if I can't find it, I'll hit the junk yards around here.

Any help would be greatly appreciated.

Thanks

 

[MrFrodo]

Well I got the module installed and the speeds work correctly now. Now I am looking for one more part. It is number 36 in the diagram on this thread. It's the flap that the temp control actuator uses. I need to see about replacing the actual flap and possibly the actuator. I took the actuator off to ensure that it is functioning properly, but in doing so, the end of the flap broke off into the actuator. I think I can get the part that broke off out, but I cannot find any information or way to search for a replacement flap. I guess if I can't find it, I'll hit the junk yards around here.

Any help would be greatly appreciated.

Thanks

Let me know what you end up doing. I just pulled my bottom actuator off and the piece broke off inside of it too. It was seriously stuck inside, I tried for 1/2 hour to gently remove the actuator. Used WD-40 and pried gently but that sucker was stuck.