A/C Problems, need more info on blend door actuators

[gocoxgo]

Okay, heres the deal, 2000 buick lesabre a/c charged and blowing colde on passenger side, blowing like a "vent" setting on drivers side.
I have read and looked at the diagrams on the sticky, but feel more confused now.
How many actuators are there?
Which one is most likely the cause, if it is the cause?
I have found two, one inside the glove dept to the rear left, and another at the very bottom drivers side left of the temperature gauge (about where your right knee would be if you were driving).
I am thinking that there are two more, kinda side by side upper drivers side under the instrument panel, is that correct? how do i get to those? I have disassembled most all my dash, taken out my instrument panel but the plastic casing looks like it connects the entire front dash.
Also, is there a way to check and see if these are working, a test of sort?
Any info will be helpful, thanks

 

[DonP]

Two blend door actuators, one for the driver side, one for the passenger side. There are also similar actuators for the recirculation and for selecting discharge (floor, defrost, dash vents). They are similar in function, but are NOT identical parts.

Judging from my 2004, The driver side blend door actuator may be the easiest to reach. See the sticky thread in this forum for some graphics on locations.

Some report that a lack of good A/C on the driver side can also be caused by a low charge - e.g., the passenger side of the evap coil eats up all the cooling.

You may be able to do a simple check for blend door function by adjusting the temp setting. If the system calls for heat you should get hot air and for cooling you should get cooler air.

My actuator was acting intermittent (not the usual railure other have reported). It would suddenly shift to blow hot air (not warm but hot) for a few seconds and then return to normal cold air. This may have been caused by gear grease in the actuator interfering with an accurate position rheostat reading. I cleaned the internal element a week ago and it is still acting OK. (Knock on teh immitation wood grained dash trim.)

 

[Merkava_4]

How many actuators are there?

There are three on a LeSabre Custom and four on a LeSabre Limited. (Which one do you have?)

LeSabre Custom:

- The temperature air mix actuator.
- The mode actuator.
- The air inlet actuator.

LeSabre Limited:

- The driver air mix actuator.
- The passenger air mix actuator.
- The mode actuator.
- The air inlet actuator


This drawing here refers to a LeSabre Limited:

If you have a Lesabre Limited, it sounds like the driver air mix actuator may not be working.





.

 

[gocoxgo]

I have the custome model

Like i said, I have found 2 of the actuators, one behind the glove compartment, and the other one drivers side bottom, behind the ashtray.

Also, I have checked bothe of them, and they seem to be working. When I removed them, I opened them up and visually they looked to be fine inside. I connected the wires back and turned the car on and each one seem to work.

I guess I need to find that third one in my custom and check it.
Any help would be appreciated, thanks

 

[imidazol97]

I have the custome model

Like i said, I have found 2 of the actuators, one behind the glove compartment, and the other one drivers side bottom, behind the ashtray.

Also, I have checked bothe of them, and they seem to be working. When I removed them, I opened them up and visually they looked to be fine inside. I connected the wires back and turned the car on and each one seem to work.

I guess I need to find that third one in my custom and check it.
Any help would be appreciated, thanks

The third one is the recirculation door actuator--it opens to reuse some of the air inside the car.

Let's try a different path.

Yours is a Custom. It has a control for the temperature that moves the door for the passenger and the driver as one unit with one actuator.

If you go out to the car, start it and the coolant warms up, try changing the temperature using the temp control. Do the passenger and driver side BOTH go warm when you put it on HOT? (Turn the AC off.)

Do they both go cooler when you change the setting to cooler?

If so, the temp doors are moving.

Many people experience low freon due to seepage with age. Your car is 11 years of age.

The design of the evaporator has the freon entering on the portion of the evaporator that has air for the passenger going through it. If there's low freon, that portion is cooled by evaporation of liquid freon, but there's no liquid left to cool the metal coils in the part where the driver air goes through.

Another check for low freon is to have the car running for several minutes, AC on full, high blower speed, then feel the temperature on the metal tubes going into and out of the firewall with your fingertips (if you don't have an infrared temp reader, which I've always wanted to buy). Ideally, the one going in should be warmer than the one coming out. The larger diameter tube is the OUT tube.

That would infer the freon is still evaporating even after cooling all the metal evaporator inside the HVAC box.

Another empirical test would be in the cool of the morning or night, turn on the AC and keep the blower on lowest speed. That makes little demand on the freon supply. If the driver side seems to cool about the same as the other side, that would fit that the passenger side is not using up all the freon liquid by heating it and there is still liquid to expand in the driver portion of the evaporator.

So I would now check your freon charge if you understand and know how to check with a gauge set. But Otherwise I suggest a professional garage.

 

[gocoxgo]

>If you go out to the car, start it and the coolant warms up, try changing >the temperature using the temp control. Do the passenger and driver side >BOTH go warm when you put it on HOT? (Turn the AC off.)

yes, they both get hot

>Do they both go cooler when you change the setting to cooler
yes, but only "vent" cool on drivers side

I have found my 3rd actuator. This one is in the far rear of the glove compartment,very near the passenger sidewall. This one is very difficult to get a ratchet on ( I have already lost one socket).
I did cut the car on and play with the a/c controls as i put my finger over the cam. I did not feel it move at all. I also unplugged the wires and did not notice any difference in what my a/c was doing.

which actuator is this one and what does it do?
Could it be bad because I did not feel the cam move?

I dont know if I want to go any further with this one, it seems so hard to get to ( i have already lost one socket)

 

[FredT]

I read the “sticky” on Blend Door Actuators, but am not convinced that this is my problem.
The air flow from the panel vents will intermittently quit blowing from the panel vents and then start blowing out of them again after a few minutes as if the actuator door opens and closes all on its own.
I’ve been to an a/c mechanic who said he can’t diagnose the problem unless it quits completely. It’s kind of like a pain that goes away when you go see the Doctor.

 

[imidazol97]

>
I have found my 3rd actuator. This one is in the far rear of the glove compartment,very near the passenger sidewall. This one is very difficult to get a ratchet on ( I have already lost one socket).
I did cut the car on and play with the a/c controls as i put my finger over the cam. I did not feel it move at all. I also unplugged the wires and did not notice any difference in what my a/c was doing.

which actuator is this one and what does it do?
Could it be bad because I did not feel the cam move?

I dont know if I want to go any further with this one, it seems so hard to get to ( i have already lost one socket)

That sounds like the recirculation air control. It is NOT your problem, at least in my analysis.

When you tried the temperature controls, did the temp cool off to ambient temperature intake (from the HOT) when you moved the control back to cool--without the AC compressor working?

Another check for low freon is to have the car running for several minutes, AC on full, high blower speed, then feel the temperature on the metal tubes going into and out of the firewall with your fingertips (if you don't have an infrared temp reader, which I've always wanted to buy). Ideally, the one going in should be warmer than the one coming out. The larger diameter tube is the OUT tube.
.

How about the temperature of the freon tubes under the hood?

 

[DonP]

The [COLOR=blue !important][FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif][COLOR=blue !important][FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif]air [/FONT][COLOR=blue !important][FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif]flow[/FONT][/COLOR][/FONT][/COLOR][/COLOR] from the panel vents will intermittently quit blowing from the panel vents and then start blowing out of them again after a few minutes as if the actuator door opens and closes all on its own.

That sounds like an intermittent somewher in the system that controls the mode actuator. The air sudently shifting from the dash vents to the defroster vents or floor vents. and then returning. In a '79 skylark I had it was caused by a vacuum leak in the HVAC control system.

In my '04 LeSabre a shifting from cool to hot for a few seconds and back to cool on the driver side only was apparently caused by gear grease inside the actuator causing poor contact in the blend (air mix) door position sensor rheostat. But there may be other causes as well.

 

[Merkava_4]

I have the custome model

Like i said, I have found 2 of the actuators, one behind the glove compartment, and the other one drivers side bottom, behind the ashtray.

The third actuator is behind the glove compartment too, but it's a further reach up towards the engine compartment.

It's number (3) in this drawing:

 

[FredT]

That sounds like an intermittent somewher in the system that controls the mode actuator. The air sudently shifting from the dash vents to the defroster vents or floor vents. and then returning. In a '79 skylark I had it was caused by a vacuum leak in the HVAC control system.

In my '04 LeSabre a shifting from cool to hot for a few seconds and back to cool on the driver side only was apparently caused by gear grease inside the actuator causing poor contact in the blend (air mix) door position sensor rheostat. But there may be other causes as well.

Man, talk about a difficult problem to locate, "a vacuum leak in the HVAC system". How in the heck does one go about lolating that? There are a hundred vacuum hoses on this thing.

 

[FredT]

vacuum control solenoid

Would a problem with the "vacuum control", part 15-71927, cause the blend doors to act wierd? There are 8 vacuum lines on this thing.

 

[imidazol97]

Re: vacuum control solenoid

Would a problem with the "vacuum control", part 15-71927, cause the blend doors to act wierd? There are 8 vacuum lines on this thing.

Nothing on your HVAC is controlled by vacuum. In the 92-99 models, there were vacuum lines that controlled the movement of diaphragms and two electric actuators (on dual temp models).

Yours is all electric.

 

[imidazol97]

Okay, heres the deal, 2000 buick lesabre a/c charged and blowing colde on passenger side, blowing like a "vent" setting on drivers side.

When you say the AC is charged, what do you mean?

In an earlier post I asked about the temperatures of the two tubes to the AC under the hood at the firewall with the engine running and the AC on and the blower motor on HIGH. What are those relative temps based on fingertip touch?

If outlet (larger) is warmer, then you may be undercharged.

 

[FredT]

Not controlled by vacuum???
Then what is this gizmo that is behind the glovebox?
View attachment 1771

 

[dcraig1000]

whats the part number on that thing?

 

[imidazol97]

Not controlled by vacuum???
Then what is this gizmo that is behind the glovebox?
View attachment 1771

Did this topic get hijacked?

The original was a 2000:

gocoxgo

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A/C Problems, need more info on blend door actuators
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Okay, heres the deal, 2000 buick lesabre a/c charged and blowing colde on passenger side, blowing like a "vent" setting on drivers side.

 

[dcraig1000]

I do believe it has been hi jacked. Lets stick to the original post. and as stated already, its not controlled by any vacuum.

 

[FredT]

AC delco # 15-71927
Located behind the glovebox and called a "vacuum valve", so how can the system NOT be controlled by vacuum??
I don't know what "hijacked" means, but I thought the subject was "blend door" and mine is not working properly, therefore I am trying to locate the problem.

 

[dcraig1000]

We are talking about a 2000 Lesabre here. Those valves were discontinued in 99.