Yes, it's an A/C post

[kly5953]

Ok, had the vehicle 2 weeks or so. Love it, BUT....big but....the A/c has a mind of it's own. I asked it to blow hot, and it blows cold, turned it off and on again, tried hitting the A/C button, didnt work. Then the next day it works. Now, I live in GA and this might be a foreign idea to some people but, within 1 day I had to have the heater on full blast, and the A/C on full blast, and neither time did it do what I wanted. At some point it was blowing hot air on the passenger when I wanted 78° and good 78° air on me, then another time it was blowing cold on me when I wanted hot and hot on the passenger. This guy is all over the place, and I'm wondering if this sounds like a control module issue.
Please someone run me through some quick trouble shooting as I don't know where to start on this one. I'm wondering if maybe I should try pulling it out and plugging it back in to see if it starts working then.

No work has been completed other than swapping out the glove box, and the issue has been around since I got it. Up till now I just kept the air off and used the windows or the seat heaters to help out.

 

[exp500]

Do you have access to a 2way scanner like a Tech2?

 

[kly5953]

Do you have access to a 2way scanner like a Tech2?

I do not. I can maybe ask around if someone in the local atlanta area does

EDIT:

I just found a post on the chevy forum talking about this, and it looks like there might be a fix. If the unit had been replaced before, and the codes weren't reset, there could be an issue with calibration. Obviously at 175k it's possible this has happened. I am going to try removing the power cables, letting the vehicle sit for a while and then plug it back up. Then, turn the vehicle on and shut off the unit, let the hoe warm up, and turn the climate control unit back on. I'll get back to see if this works tonight.

 

[S33k3r]

Most likely the blend door actuator needs to be replaced. You are on the right track -- trying to recalibrate first. But if the actuator needs to be replaced, this is likely why the previous owner sold it.

 

[kly5953]

Do you have access to a 2way scanner like a Tech2?

Does it have to be the Tech2? a buddy of mine says he has a scanner at the shop that scans anything...I'm more old fashioned of trying to fix mechanical crap mostly so idk what i'm talking about with the scanners lol

Most likely the blend door actuator needs to be replaced. You are on the right track -- trying to recalibrate first. But if the actuator needs to be replaced, this is likely why the previous owner sold it.

From what I read, the blend door actuator only affects one side at a time, is it possible all of the actuators are bad at the same time?

 

[S33k3r]

Does it have to be the Tech2? a buddy of mine says he has a scanner at the shop that scans anything...I'm more old fashioned of trying to fix mechanical crap mostly so idk what i'm talking about with the scanners lol



From what I read, the blend door actuator only affects one side at a time, is it possible all of the actuators are bad at the same time?

I have a 2005 Suburban 2500, and it has three blend doors. One that is accessible from the driver's side, one that is accessible from the passenger side, and one that requires removal of the dash. Guess which one died on mine?

 

[kly5953]

I have a 2005 Suburban 2500, and it has three blend doors. One that is accessible from the driver's side, one that is accessible from the passenger side, and one that requires removal of the dash. Guess which one died on mine?

So after pulling the battery for about 2 hours and trying to reset it, the air is only blowing hot all the time. I havent been able to really do much else, but I can state that it's blowing hot air on both sides constantly. Would this help me to realize which blend door is bad? Cause I'm guessing it sounds like the one in the dash.

 

[S33k3r]

Have you replaced the dial,yet? If not, do you have a buddy who would let you borrow his?

 

[kly5953]

Have you replaced the dial,yet? If not, do you have a buddy who would let you borrow his?

No and No
I might have to go to the junkyard and take a look for some

I'm guessing that's the next step to see if the control unit works properly.
Is there a way to test this without replacing it with a different unit?
I can pull it from the dash and try to leave it plugged up if I can test all the wires for proper signals.

 

[S33k3r]

No and No
I might have to go to the junkyard and take a look for some

I'm guessing that's the next step to see if the control unit works properly.
Is there a way to test this without replacing it with a different unit?
I can pull it from the dash and try to leave it plugged up if I can test all the wires for proper signals.

I am sorry, but you just exceeded the limits of my knowledge. I'd search Youtube, or wait for someone with more experience on here to answer you. That said, it really sounds like the controller. If it were a blend door, it seems to me that it would blow cold in some places and hot in others. But don't take that to the bank either.

In terms of a "junkyard unit", watch FB Marketplace, Craigslist, OfferUp, etc. for part outs. Any of the GMT800 play form can have what you need, depending on the trim level. Just watch the interior pictures. I've seen those pieces go for $30-$60. At that price, it doesn't hurt to have one as a spare, even if that doesn't turn out to be the problem. And, you never know, you might find one where the button pictures aren't worn completely off...

Good luck.

 

[kly5953]

Anybody know how to trouble shoot this thoroughly?
Also worth noting that the air was blowing in the wrong place for about 20 minutes the other day. Had it set to blow on face and it was hitting the windshield for about 15 minutes or so after the vehicle had warmed up.

Luckily I do have time cause it's getting cold so the heater being stuck on is not too bad

 

[kly5953]

Well, just realized my unit didn't fully reset, so i'm going to retry that tonight

 

[kly5953]

So I did a reset of the AC again last night. While it went through a 2 minute cycle reset, it blew hot, cold, and medium air. This morning while I'm driving, it blew 74° air right off the bat, so we were good there, then I turned it down to 60° and it blew colder air, but when I turned it up to 90°, the passenger side started blowing hot, but the driver didn't.
I played with it for a bit, and the only time the passenger side didn't do things right, was when I changed the temp drastically(like from 90 to 60) and it wouldn't blow any air for a minute or two.
So after that I set it to 75, and my driver side air blew some room temp air, then kinda warm air, then room temp, then kinda warm, etc.
Does this sound like a driver side actuator?

 

[S33k3r]

It sounds like an actuator. I don't know if it is the driver's side or the middle one. The experience I had was it was 100 degrees outside, my passengers enjoyed ice cold AC, and the driver "enjoyed" broiling hot heat. Did I mention it was 100 degrees outside already? Anyway, it can't hurt to look at the ones that are easiest to access. And I really HOPE it is not the center one.

 

[kly5953]

It sounds like an actuator. I don't know if it is the driver's side or the middle one. The experience I had was it was 100 degrees outside, my passengers enjoyed ice cold AC, and the driver "enjoyed" broiling hot heat. Did I mention it was 100 degrees outside already? Anyway, it can't hurt to look at the ones that are easiest to access. And I really HOPE it is not the center one.

So how do I check if the actuator is the problem? Do I need that scanner, cause I can do it, just might be a week or so before I can get to it.

And what is a good brand of blend door actuator? doorman? ACDelco?

 

[kly5953]

Anyone.....?
Anyone?
Bueller?