Stuck recirculate a/c door

[texdave]

I have a 99 K1500 Suburban and noticed that the A/C was not feeling as cold as it should be during the hottest days of the year here in Texas. Took the truck to get the A/C looked at and the pressure levels look good, the A/C controls work, and the major A/C components under the hood all check out fine.

What the tech found was that the recirculate door that the actuator moves does not close fully when the recirculate button is pressed (or temp control is set to max) and that allows some hot/humid air to get into the vents. The actuator was tested and found to be good. If you tried to move the door manually, it does not move easily.

To fix it, I was quoted 10 hours worth of labor due to the door only being accessible by removing the dash. Has anyone been in a similar situation and how did you handle it? Is that door not accessible any other way?

 

[someotherguy]

The mechanism is a pretty simple one so all I can imagine is some piece of debris is preventing the door from closing and sealing properly, or perhaps the rubber seal at the edge of the plastic door has deteriorated.

To get in there, yes, the dash needs to come out first, a/c system evacuated, and the whole a/c box removed from the firewall. It's not fun. It's less fun on 1995-up models like your 1999 simply because pulling the dash is a bit more work than the earlier 1988-1994 interior design, but neither is fun.

It's not totally implausible that one might get just that section of the a/c box out without removing the dash, but I don't really think it's possible. The box is an assembly of 3 sections. Blower motor housing also has the fresh air intake from the cowl and of course below that is the door for fresh air/recirculate. Middle section has the evaporator core and heater core along with the door that controls the temperature mix between the two. Finally leftmost is the air distribution with doors that direct airflow to the floor, dash, or defrost vents.

There are 4 screws holding the blower housing to the middle section; IF you could possibly reach the top 2 screws (rearmost by the firewall likely most difficult), the 2 lowers aren't so bad, and then the 3 screws under the hood holding that section to the firewall - *you might* be able to wiggle the housing loose and down, but I still believe the dashboard would interfere with you getting that section down and out so you could work on it.

This pic is the view of the box where it sits against your firewall. Large rectangular opening on the left is where it draws fresh air in from the wiper cowl area on the passenger side. The fresh air/recirculate door is at the bottom of that assembly; you can see the actuator motor for it at bottom right corner, and of course hiding underneath/behind all that is the blower motor.

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I'd love to be wrong about having to pull the dash for this. I suspect that even if you can reach all 4 screws to detach that section, the size/shape of the blower motor housing will still be a problem and require you to pull the dash. It's food for thought, anyway.

I just pulled the dash from my '93 (it was falling to pieces and needed to come out anyway) and pulled the a/c box to replace the evaporator core. IMO, no way to replace the evap without doing the "whole job" due to the way the middle section of the box comes apart.

Richard

 

[AK49BWL]

He's right about having to remove the dash to access the door itself.. in fact the entire HVAC box has to be pulled out, which means a full system evac and all the fun stuff that entails. What most likely happened is the rubber edges of the door have rotted off so the door can't seal. Best part? You can't get that door new anymore.

 

[someotherguy]

He's right about having to remove the dash to access the door itself.. in fact the entire HVAC box has to be pulled out, which means a full system evac and all the fun stuff that entails. What most likely happened is the rubber edges of the door have rotted off so the door can't seal. Best part? You can't get that door new anymore.

I've had several of these boxes out of trucks (with full dash removal of course) and pulled a few apart for cleaning, evap replacement, etc. and most recently as mentioned just last week. Looking at it sitting in the truck with the dash still out, it seems plausible to me that you could get the blower motor housing off of the box assembly without removing the whole box, saving you the extra hassle of evacuating the a/c (and also the lesser hassle of disconnecting the heater core.) With the dash out of the way you can reach all 4 of the interior screws although that top rearmost one is still a little tricky.

This might be a useful approach for people wanting to do a weatherstrip seal replacement at the top of the fresh air inlet, too, without having to remove the whole box. But, since you've already done the work to pull the whole dash.. it's just saving you from cracking open the a/c system itself.

Richard

 

[texdave]

Thanks all for the detailed information on how the in-cabin ventilation system is setup in our trucks, especially that picture someotherguy. Appreciate you confirming the work involved in dealing with that door.

I fear I'm more or less in the same position the previous owner was with this where it likely doesn't make sense to pay someone to do it for me. Perhaps I can try tackling it myself if I find myself with more time.

 

[someotherguy]

Thanks all for the detailed information on how the in-cabin ventilation system is setup in our trucks, especially that picture someotherguy. Appreciate you confirming the work involved in dealing with that door.

I fear I'm more or less in the same position the previous owner was with this where it likely doesn't make sense to pay someone to do it for me. Perhaps I can try tackling it myself if I find myself with more time.

Later the same day that you started this post, @Schurkey posted a picture in a different thread, where he had in fact removed the blower motor housing from the a/c box without removing the box from the firewall. So that's one big hurdle you wouldn't have to jump.

Richard