2006 Lacrosse CXL Blend Door Actuator Location?

[Rich7553]

My 2006 LaCrosse has no heat! Being in southern Florida, I didn't notice it until a cool morning last week. It appears all diverters are working, both heater core hoses are hot at operating temperature.

Can someone tell me where the heater core blend door actuator is located and where the easiest access point is?

 

[Buick Customer Service]

I would be happy to look into this for you with the last eight of your VIN. Please feel free to contact me privately and I will be able to do further research. Thank you.

Tricia, GM Customer Service.

 

[Rich7553]

I would be happy to look into this for you with the last eight of your VIN. Please feel free to contact me privately and I will be able to do further research. Thank you.

Tricia, GM Customer Service.

Hi Tricia,

The last 8 of the VIN are: 61227620. Thanks for your help.

Rich

 

[Road Dog]

It is good to see TRICIA working it. Hope she is the real GM, not a subcontractor.They need to help their most valued asset "the customer" MORE. Here is the way it should go- "BFACE", BUICK FACTORY ACHIEVING CUSTOMER EXPECTIONS. REMINDING THEM WHO THEY REALLY WORK FOR Every day. And then post pics of a different satisfied service warranty customer in their factories, at their dealers & GM's web sites. This is how csi really begins! And wouldn't you know it, they'd sell more cars!? This post didn't get your question answered, but Tricia is on it! Good luck to both of you. Happy Motoring! RD

 

[Buick Customer Service]

Rich,

Thank you for the response. I am looking into this for you and hope to get an answer for you by Monday. Thank you again for your patience.

Tricia, GM Customer Service.

 

[Road Dog]

Hey Rich Let me share a note or two with you while Tricia is doing some research concerning your problem. Should have told you this to start with. Taking these dashes apart is pandora's box. I'll make it quick, the modulating damper(air temp blend-door) is controlled by what is known as BCM (body control module) that has different settings in it for blending the air. I am reasonably sure that the swivel rotor is broken on the blade, thus stuck shut, caused by the BCM that is out of calibration or just worn out, thus over-torquing the blade, not shutting itself off in time, pushing it against the stop, while still running, causing the rotor shaft to break. Maybe $130-$140 for the BCM, probably $50-$60 for the blade, GM propriatory parts-dealer only. 99 9/10% sure dash has to come apart. Wouldn't begin to guess shop labor. Shot from hip $500-$700 labor, maybe. Hope I'm wrong, fingers crossed for you for better news from Tricia. Happy Motoring! RD

 

[Rich7553]

Hey Rich Let me share a note or two with you while Tricia is doing some research concerning your problem. Should have told you this to start with. Taking these dashes apart is pandora's box. I'll make it quick, the modulating damper(air temp blend-door) is controlled by what is known as BCM (body control module) that has different settings in it for blending the air. I am reasonably sure that the swivel rotor is broken on the blade, thus stuck shut, caused by the BCM that is out of calibration or just worn out, thus over-torquing the blade, not shutting itself off in time, pushing it against the stop, while still running, causing the rotor shaft to break. Maybe $130-$140 for the BCM, probably $50-$60 for the blade, GM propriatory parts-dealer only. 99 9/10% sure dash has to come apart. Wouldn't begin to guess shop labor. Shot from hip $500-$700 labor, maybe. Hope I'm wrong, fingers crossed for you for better news from Tricia. Happy Motoring! RD

Yikes! That doesn't sound like it would be any fun at all. Okay, if that's the case, I'm gathering that the BCM acts as the controller for the various actuators?

 

[Road Dog]

No Rich It doesn't. The component description the auto guys use would make you think that it controls the landing gear on a 747. I'll try to explain this as simple as possible. The BCM is a little black box maybe 2" x 2" with a female spleened insert in the middle of it that is turned by a little worm gear that represents the blade travel from side to side and the variations in between. The blade shaft on one end fits into this box and it is moved by little electric pulses which are acting on the control command. These little electrical pulses are known as sones which in effect moves the damper.The best I can tell that is the sole fuction of the BCM. I also might add that the ducting of this starts just inside the firewall under the dash. A 1/4" metric set is required plus pliers, phillips flat screwdrivers, etc. All the connectors underneath it are Delphi connections. The biggest pain in the butt is getting these plastic expandable molly style fastners removed without damage for reuse. This failure in not inclusive to Buick. It's across the GM line. The contracted Buick rep will not tell you anything, any information is on a need to know basis. I sure hope it's something else. The older style dampers used pneumatic regulators which would go bad occasionally. These little electrical control regulators have such small internal wiring that resistance builds up in them, gets hot and just can't function as designed. I'd be curious to see how the rep explains this. Beings now she already has the answer. Otherwise probably clueless. Hope this helps. Happy Motoring! RD

 

[Rich7553]

No Rich It doesn't. The component description the auto guys use would make you think that it controls the landing gear on a 747. I'll try to explain this as simple as possible. The BCM is a little black box maybe 2" x 2" with a female spleened insert in the middle of it that is turned by a little worm gear that represents the blade travel from side to side and the variations in between. The blade shaft on one end fits into this box and it is moved by little electric pulses which are acting on the control command. These little electrical pulses are known as sones which in effect moves the damper.The best I can tell that is the sole fuction of the BCM. I also might add that the ducting of this starts just inside the firewall under the dash. A 1/4" metric set is required plus pliers, phillips flat screwdrivers, etc. All the connectors underneath it are Delphi connections. The biggest pain in the butt is getting these plastic expandable molly style fastners removed without damage for reuse. This failure in not inclusive to Buick. It's across the GM line. The contracted Buick rep will not tell you anything, any information is on a need to know basis. I sure hope it's something else. The older style dampers used pneumatic regulators which would go bad occasionally. These little electrical control regulators have such small internal wiring that resistance builds up in them, gets hot and just can't function as designed. I'd be curious to see how the rep explains this. Beings now she already has the answer. Otherwise probably clueless. Hope this helps. Happy Motoring! RD

Okay, I'm confused. According to the wiring diagrams I have, there are five air temperature sensors: 1) inside air temperature, 2) upper left air temperature, 3) upper right air temperature, 4) lower left air temperature, and 5) lower right air temperature. These five sensors all feed the HVAC control module. The HVAC control module has four outputs: 1) recirculation actuator, 2) air temperature actuator - left, 3) air temperature actuator - right, and 4) mode actuator.

Are you sure you're not referencing the HVAC control module instead of the BCM? I've gone over every wiring diagram associated with the BCM and you're right, it has inputs and outputs for everything from the windshield wipers to the trunk ajar switch, but I don't see a single reference to air temperature associated with it.

 

[Buick Customer Service]

Rich,

Thank you again for your patience. I am showing that the heater core blend door actuator is located in the right side of the dash by the heater case. I hope this helps.

Tricia, GM Customer Service.

 

[jft69z]

disregard this one....

 

[jft69z]

Okay, I'm confused. According to the wiring diagrams I have, there are five air temperature sensors: 1) inside air temperature, 2) upper left air temperature, 3) upper right air temperature, 4) lower left air temperature, and 5) lower right air temperature. These five sensors all feed the HVAC control module. The HVAC control module has four outputs: 1) recirculation actuator, 2) air temperature actuator - left, 3) air temperature actuator - right, and 4) mode actuator.

Are you sure you're not referencing the HVAC control module instead of the BCM? I've gone over every wiring diagram associated with the BCM and you're right, it has inputs and outputs for everything from the windshield wipers to the trunk ajar switch, but I don't see a single reference to air temperature associated with it.

You are correct Rich, the HVAC control module determines the actuator control motor positions, NOT the BCM (body control module). The little "2x2" black box that Roaddog was referencing earlier in post #8 is the
actuator motor, not BCM which may have been a bit confusing (no offence intended RD).

You can also scan the vehicle & see if there are any codes associated with the HVAC system. You will need to find someone with a Tech 2 or a Snap On Modis scan tool to see what is going on. All of those door actuators have feedback and will usually spit a code if one is bad. I've changed a bunch of them on GM vehicles. Of course, if the door is broken but the actuator is still going thru it's full range of motion then it will assume the actuator is still good (which it is). If the door is busted, the first step of the repair procedure says....remove HVAC module assembly from vehicle. It's pretty involved from there.

First step is to see if the actuator motors are working properly, if they are then you're probably looking at the door issue.

 

[Rich7553]

You are correct Rich, the HVAC control module determines the actuator control motor positions, NOT the BCM (body control module). The little "2x2" black box that Roaddog was referencing earlier in post #8 is the
actuator motor, not BCM which may have been a bit confusing (no offence intended RD).

You can also scan the vehicle & see if there are any codes associated with the HVAC system. You will need to find someone with a Tech 2 or a Snap On Modis scan tool to see what is going on. All of those door actuators have feedback and will usually spit a code if one is bad. I've changed a bunch of them on GM vehicles. Of course, if the door is broken but the actuator is still going thru it's full range of motion then it will assume the actuator is still good (which it is). If the door is busted, the first step of the repair procedure says....remove HVAC module assembly from vehicle. It's pretty involved from there.

First step is to see if the actuator motors are working properly, if they are then you're probably looking at the door issue.

Got it. Now one final question for clarification. I'm trying to think this through before I start tearing into the underside of the dash. My LaCrosse has individual temperature controls, yet through trial and error, it appears that I have no heat whatsoever, through neither floor register nor the windshield defroster register. According to my wiring diagrams the automatic temperature control version, there is no single actuator that opens the door to the heater core. Is that correct or is there such an actuator and if so, is it located on the right side of the heater case as Tricia stated?

 

[jft69z]

According to my wiring diagrams the automatic temperature control version, there is no single actuator that opens the door to the heater core. Is that correct or is there such an actuator and if so, is it located on the right side of the heater case as Tricia stated?

If you have the automatic system, it appears that there is not one common temp actuator as you suspect. It uses the left & right actuators for temperature control. The other 2 actuators should be for recirculation air flow & the mode actuator (defrost, panel, floor).

It looks like the right side actuator is located on the right side, slightly below the "mode" actuator. The left side actuator is on the left side close to the center of the car, and the air recirc actuator is on the far right side of the car near the blower motor.

One thought, has the battery been disconnected in the past? If so it may be possible that the actuators need to go thru a recalibration procedure. Also whenever replacing the HVAC control module or any of the actuators the procedure must be performed. The most important part is DO NOT touch any controls on the HVAC control module during the process while it is self calibrating or improper HVAC performance will result.

Without a scan tool, it says to:

1)Clear all DTC's (diagnostic trouble codes)
2)Ignition switch OFF
3)Install actuators (if replacing them)
4)Remove the HVAC/EACS fuse for a minimun of 10 seconds
5)Reinstall the fuse
6)Start the vehicle
7)Wait 40 seconds for the HVAC system to self-calibrate
8)Verify that no DTC's have set as current codes

The automatic system is fairly complex in regards to all the duct sensors, inside & outside temp sensors, sunlight sensors etc. Have you tried the system in full auto mode? Like I mentioned earlier, a scan tool would be helpful here, however I realize most don't have simple (or free) access to one.

 

[Rich7553]

If you have the automatic system, it appears that there is not one common temp actuator as you suspect. It uses the left & right actuators for temperature control. The other 2 actuators should be for recirculation air flow & the mode actuator (defrost, panel, floor).

It looks like the right side actuator is located on the right side, slightly below the "mode" actuator. The left side actuator is on the left side close to the center of the car, and the air recirc actuator is on the far right side of the car near the blower motor.

One thought, has the battery been disconnected in the past? If so it may be possible that the actuators need to go thru a recalibration procedure. Also whenever replacing the HVAC control module or any of the actuators the procedure must be performed. The most important part is DO NOT touch any controls on the HVAC control module during the process while it is self calibrating or improper HVAC performance will result.

Without a scan tool, it says to:

1)Clear all DTC's (diagnostic trouble codes)
2)Ignition switch OFF
3)Install actuators (if replacing them)
4)Remove the HVAC/EACS fuse for a minimun of 10 seconds
5)Reinstall the fuse
6)Start the vehicle
7)Wait 40 seconds for the HVAC system to self-calibrate
8)Verify that no DTC's have set as current codes

The automatic system is fairly complex in regards to all the duct sensors, inside & outside temp sensors, sunlight sensors etc. Have you tried the system in full auto mode? Like I mentioned earlier, a scan tool would be helpful here, however I realize most don't have simple (or free) access to one.

Would there be an indication of some sort like a check engine light that would indicate the presence of a DTC? My local Advance Auto Parts has a scanner, but I don't know if their scanner is one that will read the codes you mention. I will try the fuse reset in the morning and I'll let you know what happens.

 

[jft69z]

Would there be an indication of some sort like a check engine light that would indicate the presence of a DTC? My local Advance Auto Parts has a scanner, but I don't know if their scanner is one that will read the codes you mention. I will try the fuse reset in the morning and I'll let you know what happens.

Nah, the check engine light would be for the ECM. That is designed to do anything possible to diagnose & protect the emissions sysyem, especially the cat converter. The rest of the modules like BCM, ABS, Airbag, Instrument Panel Module, TPM & HVAC won't trigger the check engine light for the above mentioned reasons. They will set codes, but you need more than a basic code reader to get to them. I don't know what Autozone uses, but it's worth a shot. They will need to be able to get to the HVAC module to pull codes. With my scan tool I can also see real time data and do functional tests on the actuators, doors, blowers and the like to narrow down the troubleshooting to a specific component, plus do the recal on the system. If they can do that it would be great, but I highly doubt it.

 

[Rich7553]

Nah, the check engine light would be for the ECM. That is designed to do anything possible to diagnose & protect the emissions sysyem, especially the cat converter. The rest of the modules like BCM, ABS, Airbag, Instrument Panel Module, TPM & HVAC won't trigger the check engine light for the above mentioned reasons. They will set codes, but you need more than a basic code reader to get to them. I don't know what Autozone uses, but it's worth a shot. They will need to be able to get to the HVAC module to pull codes. With my scan tool I can also see real time data and do functional tests on the actuators, doors, blowers and the like to narrow down the troubleshooting to a specific component, plus do the recal on the system. If they can do that it would be great, but I highly doubt it.

Well, I reset the system per your instructions by removing the fuse, and no change. I visited both Advance Auto Parts and Autozone and neither had the scanner necessary. However, I called my local mechanic and he's got the scanner and will diagnose the problem for $40. Will take it in on Friday.

 

[jft69z]

When you go from heat to cool can you feel if the actuators are moving?

How many miles are on the car? Have you had a coolant flush lately? Just because the lines going into & out of the heater core are warm does not mean that there is not a partial blockage. I see that a bunch around here. The way I flush the heater core is to remove both lines going to the heater core and flush it both ways, not just a reverse flush of the cooling system itself. The way I do it eliminates any doubt about the heater core. I also put the discharge hose into a 5 gallon bucket to see exactly what came out of there.

At any rate, let us know how you make out on Friday.

 

[Rich7553]

When you go from heat to cool can you feel if the actuators are moving?

How many miles are on the car? Have you had a coolant flush lately? Just because the lines going into & out of the heater core are warm does not mean that there is not a partial blockage. I see that a bunch around here. The way I flush the heater core is to remove both lines going to the heater core and flush it both ways, not just a reverse flush of the cooling system itself. The way I do it eliminates any doubt about the heater core. I also put the discharge hose into a 5 gallon bucket to see exactly what came out of there.

At any rate, let us know how you make out on Friday.

Good questions. I'm going to flush the heater core both ways just to make sure that's not the problem. It could very well be the issue. The car has 101K miles on it. About 6 months ago, I had what I thought was a gasket let loose and I (like a dummy) introduced some of that sealer stuff with the copper dust in it into the system to try to hold back the leak until I could get it to the mechanic. Turns out it was the little plastic elbow fitting just above the water pump that was splitting at the seam. Had it replaced, but the mechanic didn't flush the heater core to my knowledge. I distinctly remember the heat working prior to that, as I ran the heater in order to lower the temperature so I could get it to the mechanic without cooking the engine. So I know it worked back then. In Florida, we go at least 8 months without having to use any heat function whatsoever.

I'll let you know what comes out of the system.

 

[jft69z]

Good questions. I'm going to flush the heater core both ways just to make sure that's not the problem. It could very well be the issue. The car has 101K miles on it. About 6 months ago, I had what I thought was a gasket let loose and I (like a dummy) introduced some of that sealer stuff with the copper dust in it into the system to try to hold back the leak until I could get it to the mechanic. Turns out it was the little plastic elbow fitting just above the water pump that was splitting at the seam. Had it replaced, but the mechanic didn't flush the heater core to my knowledge. I distinctly remember the heat working prior to that, as I ran the heater in order to lower the temperature so I could get it to the mechanic without cooking the engine. So I know it worked back then. In Florida, we go at least 8 months without having to use any heat function whatsoever.

I'll let you know what comes out of the system.

That elbow failure is pretty common too. The sealer could have found its way into the core and caused a blockage. A lot of people bitch about Dex-Cool antifreeze gelling up, but I don't usually see it to be a problem if you change it like you're supposed to. The bigger issue most of the time is intake gasket failure on a lot of the engines that introduces oil into the cooling system. Then it seems to gel up a bit and can cause issues. I don't consider that to be Dex-Cools fault.