Disconnected battery, blowing cold air when heat is on

[Mike534x]

I've got another problem, it feels like I've entered a domino effect with the repairs being done to the Envoy so far. My latest issue is that my heat isn't working properly, and it was fine up until I had the battery disconnected. Long story short, PCM was sent out for a tune and had DoD disabled. Hooked everything up, used the A/C for a bit (took awhile to get cold) this week because of s sudden heat wave, and now we're back in the 40 deg range. Turned the heat on, had the climate control set to 80 and it blew cold/warmish. Everything is fine if you crank it to 90, but once you back it down to 85 or under it blows cool....almost like the the outside air is blowing in. I have tried to do an HVAC reset, pulled the 10A fuse for 15-20 seconds, got in, turned the key to on and let the doors calibrate for 90 seconds and then started it up without much of a difference.

 

[Tiggerr]

Sounds like a blend door actuator crapping out...

 

[Mike534x]

I hope not, don't really have much of an idea of where to begin to tackle it. I assume the driver and passenger side both have a blend door actuator, its just a matter of, which one is it. Both vents blow the same temperature wise, before the HVAC reset the driver was warmer, while the passenger side blew cooler.

 

[Tiggerr]

IIRC there's 3...hot/cold, left/right, top/bottom...

my thinking would be, if I'm gonna pull it all apart I'm changing them all..

Unless it's not that hard to do them...

I assume it's a royal PITA like most under dash stuff.
Although blower and resistor wasn't too bad to do

I'm thinking someone on here did a write up on changing them...

 

[Reprise]

I'm thinking someone on here did a write up on changing them...

There are a few threads, which shouldn't be too hard to find - and Roadie even posted a GM-supplied diagram showing the location of all five (I'm pretty sure I have that image stored on my laptop, if the OP can't find the post.)

Of the five, the one that controls the flow from the vent vs. floor is probably the easiest to get to (when this one goes out, you get air from the defroster outlet and the floor, full-time).

There's one in the passenger side of the dash that's absolute murder, from what I remember. To get to all five, I'm pretty sure you have to remove most of the main dash assembly, which takes a long time.

 

[Capote]

Loooooong thread dedicated to the Actuators:
http://forums.trailvoy.com/showthread.php?t=40235

Closer look at driver's side:

 

[Matt]

If it's the blend door actuator, it's the worst one on the drivers side to get at because of a metal bracket that sits in front of it. It's doable, but be prepared for blood and a lot of swearing. If you have lady sized hands, you'll be OK, but man hands make it quite a bit harder.

 

[Capote]

If it's the blend door actuator, it's the worst one on the drivers side to get at because of a metal bracket that sits in front of it. It's doable, but be prepared for blood and a lot of swearing. If you have lady sized hands, you'll be OK, but man hands make it quite a bit harder.

Don't forget about your arms feeling like they're dying, having them up in the air forever losing blood

 

[Mike534x]

Oh I did see the diagram and thread on the old site! My heart sunk seeing how much work it would take to get to it, and if happens to be one of the ones behind the dash there is absolutely no way I can get that out. We have the tools, its more of a "do I trust myself to pull this thing out (the dashboard) and have everything go back the way its suppose to go" type deal.

The one of the floor on the drivers side seems doable.....unfortunately my man hands are a little too big, so I guess this thing is getting a blood sacrifice at some point and hopefully it appeases it. I left the fuse for the HVAC pulled all night, there seems to be a slight improvement when I managed to get some heat this morning.

 

[Mike534x]

Well crap, looks like I'm ripping out the bottom half of the drivers side dash. Finally had a chance to the use the heat, and only the drivers side is blowing cool with the temp at 80. Passenger side vents all blow nice and warm. I did notice that when switching modes after turning the controls on, (seems to do it when switching to floor only, or vent + floor) that it makes 1 or 2 clicking sounds and then goes away. It doesn't do it all the time when switching, but it happens after you leave the system off for a while.

So now that I'm almost positive its the drivers side blend door causing my cool air issue, I'm assuming the clicking I'm hearing is the plastic gear being partially stripped/cracked when it changes its position?

 

[Mooseman]

That would be it. It's done.

 

[Mike534x]

Thanks @Mooseman!

Is Dorman decent as far as actuators go, or would A/C Delco be better?

 

[Tiggerr]

Thanks @Mooseman!

Is Dorman decent as far as actuators go, or would A/C Delco be better?

If it was me I'd go AC Delco...
Not a Dorman fan for anything electrical...

 

[Mooseman]

Although I haven't anything specifically about their actuators, as mentioned, anything electrical from Dorman is iffy at best. I'd go ACDelco.

 

[Mike534x]

I bought the AC Delco blend door, however I ran into a snag. I was able to follow the instructions in the link from TV showing how everything comes down. The issue I ran into is that, GM changed the underside a bit preventing me from gaining access to the top screw of the blend door. Instead of a open center of the support bracket, they added a "plate" so that cover most of the actuator and the top screw.

My hand was just small enough to squeeze into the tight space to try and "bend" it out of the way but it appears there are two bolts holding it on the side right above where the actuator is. I could get a socket on there, but I cant get the wrench in the tight space. I've got a picture of whats stopping me, but I think the wrench was hitting part of the firewall, or part of the steering shaft or part of the duct work. Got my hand nice and scratched up a bit, and silly me had the fuse pulled so now both sides are back to blowing cold with the heat on 80, but the click I mentioned is gone now. This is becoming such a pain haha.

 

[gpking]

That added solid part is odd, I guess it changed at some point. My driver's side was a tight squeeze, but I got it out with no "modifications".
I did have to butcher the similar bracket on the passenger side. I just went in there with a cutoff wheel and cut right through the parts that were in the way.

There is a fuse in the rear fuse block which seemingly only controls the blend doors. That was actually my problem, I accidentally pulled the fuse and put it back in a blank slot. Maybe check that (HVAC fuses) if you haven't already.

 

[Mooseman]

That plate I also have on my 9-7x. IIRC, I was able to pull it out but there was one bolt from the backside that was a PITA. When I put it back, I omitted that bolt.

 

[Mike534x]

That added solid part is odd, I guess it changed at some point. My driver's side was a tight squeeze, but I got it out with no "modifications".
I did have to butcher the similar bracket on the passenger side. I just went in there with a cutoff wheel and cut right through the parts that were in the way.

There is a fuse in the rear fuse block which seemingly only controls the blend doors. That was actually my problem, I accidentally pulled the fuse and put it back in a blank slot. Maybe check that (HVAC fuses) if you haven't already.

All fuses in the rear are fine, I tried doing the HVAC recalibration 3 times and still no luck. Last time it fixed the passenger side heating issue, now its back after this recent reset. Just seems odd to have the heating blow cold with the temp set where it is. 90 its hot like its supposed to be, but anything under its cool/cold.

Upside is I know how this comes apart now, downside is, I wish I had that opening like everyone else has haha. This would be much easier if I had a Tech II, just so I can go in and test them to see which one is the issue, or if it just needs a reset done by the tool itself.

That plate I also have on my 9-7x. IIRC, I was able to pull it out but there was one bolt from the backside that was a PITA. When I put it back, I omitted that bolt.

I was really tempted to take a cutting wheel to it, but I was afraid of nicking any wiring hidden behind there, or damaging something I wasn't supposed to. Mine had two, but they looked like nuts, compared to the rounded nuts on the side that is accessible. I did try getting the other two out, but I really have no room to get the wrench and socket in. I was able to back the plate off enough to bend it to see the two nuts on the side its attached to, but that's as far as I could go.

 

[Mektek]

If you don't want to remove the entire dashboard, then to get to some of the actuators it is necessary to use a dremel and cutting wheel and remove some of the steel bracket that prevents you from fitting a small ratchet on the screw. After I replaced the actuator I bolted the piece that I cut out back in and reattached it.

 

[Mike534x]

Looks like I'll take a dremel to it, it's not so much the bracket but the piece in the middle where it's normally "open" going off of past guides for replacing the blend door. The passenger side blowing cool now, has me going nuts. I'm hoping the passenger side actuator isn't going as well even though it seems easier to replace so far.

 

[ttcfan4476]

any luck on this mine is doing the same thing? I can get blend door actuators thru my work for a decent price, just not sure if they are the problem. I took one of the actuators apart last night and messed with it, if I center it and plug it back in it sweeps one way and then pegs out the other and stays there no matter the heat settings.

 

[Mooseman]

You might have messed it up if you didn't realign the gears properly. Might have to replace it.

Have you tried resetting the HVAC by pulling the HVAC-B fuse for 30 seconds, putting it back in, turn the key to run but don't start, let it do its thing.