Blower runs after shut off

jaktomas1

Original poster
Member
Sep 11, 2012
7
2005 TB dual electronic climate control ... Blower fan often continues to run after ignition is turned off. If the key is turned on and off again it stops.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR

Simon01

Member
Dec 5, 2011
116
If you're talking about the digital climate control (without the sliders) I thought there was an afterblow function to prevent the nasty moldy smell when the AC is on. If it runs just for a minute or two, then I don't think there is an issue. Maybe someone who actually has the climate control can chime in.
 

Simon01

Member
Dec 5, 2011
116
I knew I wasn't imagining this!

#05-01-39-002A: Musty Odor from HVAC System (Reprogram HVAC Control Module to Enable Afterblow Function) - (Mar 17, 2006)

Subject: Musty Odor from HVAC System (Reprogram HVAC Control Module to Enable Afterblow Function)

Models: 2004–2006 Buick Rainier
2003–2006 Chevrolet TrailBlazer, TrailBlazer EXT
2003–2006 GMC Envoy, Envoy XL
2004–2005 GMC Envoy XUV
2003–2004 Oldsmobile Bravada

with Automatic Temperature Control HVAC System (RPO CJ2)
--------------------------------------------------------------------------------

This bulletin is being revised to add the 2006 model year and update the calibration release date. Please discard Corporate Bulletin Number 05-01-39-002 (Section 01— HVAC).

--------------------------------------------------------------------------------
Condition

Some customers may comment on a musty odor from the Heating, Ventilation and Air Conditioning (HVAC) system. This condition occurs most often on initial start up after the vehicle was driven on a hot humid day.

Cause

This condition may be caused by condensate build-up on the evaporator core, which does not evaporate by itself in high humidity conditions.


Correction

Important: The afterblow function should not be enabled until after the purpose and operation of it is explained to your customer and they approve of the change. Once the afterblow function is enabled there are no calibrations currently released to disable it.

Technicians are to reprogram the HVAC Control Module with an updated software calibration that will enable the afterblow function. The new calibration will be released beginning with TIS satellite data update version 2.0, which was made available February 5, 2006. The blower motor will turn on approximately 10 minutes after the vehicle is shut off. The blower motor will run continuously for 10 minutes at a 30% duty cycle. The afterblow function will only activate if the air conditioning compressor was engaged during conditions of high ambient temperature. If the vehicle is started within 10 minutes of the last key off, the afterblow function from the previous key cycle will be cancelled.

Technicians should not attempt to reprogram a vehicle with a Manual Temperature Control HVAC system (RPO CJ3).

Technicians should perform this HVAC Control Module reprogram instead of installing the Electronic Evaporator Dryer Module Kit referred to in the Air Conditioning Odor bulletin, Corporate Bulletin Number 99-01-39-004A .
 

jaktomas1

Original poster
Member
Sep 11, 2012
7
Thanks Simon01, I'll sleep better tonight... I was imagining the blower turning on in the middle of the night and killing the battery. And we all know the havoc that plays with the HVAC control systems.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Simon01 said:
I knew I wasn't imagining this!
I'm astonished. A 2006 TSB for afterblow. :eek: Thanks! Sounds like you have to ask for it to get installed. Not sure this was a software update applied at the factory to all vehicles.

Just to be clear - it says this new function doesn't leave the blower running immediately after you turn off the key. It says that 10 minutes AFTER you turn off the key, it comes back on for 10 minutes at 30% power under certain conditions.

If the blower stays running immediately after you turn off the key, I think it's still the speed control module. A good experiment is to try to get the blower to stay on, then leave the ignition alone and see if it quits after 10-20 minutes. If not, then cycle the ignition on and off again to try to get it to quit. Or see if you can get it to run at ignition off time, at full power, and see if it stays running at full power, or throttles back to the 30% mentioned in the TSB.
 

Denali n DOO

Member
May 22, 2012
5,596
the roadie said:
I'm astonished. A 2006 TSB for afterblow. :eek: Thanks! Sounds like you have to ask for it to get installed. Not sure this was a software update applied at the factory to all vehicles.

Just to be clear - it says this new function doesn't leave the blower running immediately after you turn off the key. It says that 10 minutes AFTER you turn off the key, it comes back on for 10 minutes at 30% power under certain conditions.

If the blower stays running immediately after you turn off the key, I think it's still the speed control module. A good experiment is to try to get the blower to stay on, then leave the ignition alone and see if it quits after 10-20 minutes. If not, then cycle the ignition on and off again to try to get it to quit. Or see if you can get it to run at ignition off time, at full power, and see if it stays running at full power, or throttles back to the 30% mentioned in the TSB.

I agree with Roadie. My blower started to keep on running immediately after I shut the truck off and removed the key. Mine needed a new speed control module, a new updated one at that. If your truck has the afterblow activated then it's not working the way it is suppose to. I don't think it's an afterblow function.
 

jaktomas1

Original poster
Member
Sep 11, 2012
7
After the input from Simon01 I timed the next event.. If the shoe fits.... 10 min +/- blower starts at low speed for 10.
 

DAS

Member
Oct 29, 2012
2
Simon01 said:
I knew I wasn't imagining this!

#05-01-39-002A: Musty Odor from HVAC System (Reprogram HVAC Control Module to Enable Afterblow Function) - (Mar 17, 2006)

Subject: Musty Odor from HVAC System (Reprogram HVAC Control Module to Enable Afterblow Function)

Models: 2004–2006 Buick Rainier
2003–2006 Chevrolet TrailBlazer, TrailBlazer EXT
2003–2006 GMC Envoy, Envoy XL
2004–2005 GMC Envoy XUV
2003–2004 Oldsmobile Bravada

with Automatic Temperature Control HVAC System (RPO CJ2)
--------------------------------------------------------------------------------

This bulletin is being revised to add the 2006 model year and update the calibration release date. Please discard Corporate Bulletin Number 05-01-39-002 (Section 01— HVAC).

--------------------------------------------------------------------------------
Condition

Some customers may comment on a musty odor from the Heating, Ventilation and Air Conditioning (HVAC) system. This condition occurs most often on initial start up after the vehicle was driven on a hot humid day.

Cause

This condition may be caused by condensate build-up on the evaporator core, which does not evaporate by itself in high humidity conditions.


Correction

Important: The afterblow function should not be enabled until after the purpose and operation of it is explained to your customer and they approve of the change. Once the afterblow function is enabled there are no calibrations currently released to disable it.

Technicians are to reprogram the HVAC Control Module with an updated software calibration that will enable the afterblow function. The new calibration will be released beginning with TIS satellite data update version 2.0, which was made available February 5, 2006. The blower motor will turn on approximately 10 minutes after the vehicle is shut off. The blower motor will run continuously for 10 minutes at a 30% duty cycle. The afterblow function will only activate if the air conditioning compressor was engaged during conditions of high ambient temperature. If the vehicle is started within 10 minutes of the last key off, the afterblow function from the previous key cycle will be cancelled.

Technicians should not attempt to reprogram a vehicle with a Manual Temperature Control HVAC system (RPO CJ3).

Technicians should perform this HVAC Control Module reprogram instead of installing the Electronic Evaporator Dryer Module Kit referred to in the Air Conditioning Odor bulletin, Corporate Bulletin Number 99-01-39-004A .

Can someone help me please? I have the above described problem with the musty smell air conditioning in my Buick, and no-one at GM seems to be able to find any TSB related to it. When I reference the TSB I keep finding on forums (99-01-39-004D), they say that it is not a valid TSB number and are unable to find any mention of "afterblow" or the dryer kit part number. I've been to the dealer locally and they also know nothing about it. So where do these TSB's come from if not from GM? Thanks...
 

Simon01

Member
Dec 5, 2011
116
I just pulled it from SI. Any dealer should be able to do the same.

#99-01-39-004D: Air Conditioning Odor (Install Evaporator Core Dryer Kit and Apply Cooling Coil Coating) - (Aug 10, 2011)
Subject:
Air Conditioning Odor (Install Evaporator Core Dryer Kit and Apply Cooling Coil Coating)

Models:
2012 and Prior GM Passenger Cars and Trucks
All Equipped with Air Conditioning

--------------------------------------------------------------------------------
This bulletin is being revised to add the 2011 and 2012 model years. Please discard Corporate Bulletin Number 99-01-39-004C (Section 01 – HVAC).
--------------------------------------------------------------------------------

Condition

Some customers may comment about musty odors emitted from the Heating, Ventilation and Air Conditioning (HVAC) system at vehicle start-up in hot, humid conditions.

Cause

This condition may be caused by condensate build-up on the evaporator core, which does not evaporate by itself in high humidity conditions. The odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment.

There are several other possible sources of a musty odor in a vehicle. A common source is a water leak into the interior of the vehicle or foreign material in the HVAC air distribution system. Follow the procedures in SI for identifying and correcting water leaks and air inlet inspection.

The procedure contained in this bulletin is only applicable if the odor source has been determined to be microbial growth on the evaporator core inside the HVAC module.

Correction

Many vehicles currently incorporate an afterblow function within the HVAC control module software. The afterblow feature, when enabled, employs the HVAC blower fan to dry the evaporator after vehicle shut down and this function will inhibit microbial growth. Technicians are to confirm that the customer concern is evaporator core odor and that the vehicle has the imbedded afterblow feature, as defined in the SI document for that specific vehicle model, model year and specific HVAC option. Refer to SI for enabling the afterblow function. Vehicles being delivered in areas prone to high humidity conditions may benefit from having the afterblow enabled calibration installed prior to any customer comment.
Important: If the vehicle is not factory equipped with the imbedded afterblow enable feature, it may be added with the Electronic Evaporator Dryer Module Kit (P/N 12497910 or AC Delco 15–5876).
Important: When installing the Electronic Evaporator Dryer Module, you MUST use the included electrical splice connectors to ensure a proper splice. Complete detailed installation instructions and self testing procedures are supplied with the kit. If necessary, the Electronic Evaporator Dryer Module may be installed underhood if it is protected from extreme heat and water splash areas.

To immediately remove the evaporator core odor on all suspect vehicles, it is necessary to eliminate the microbial growth and prevent its re-occurrence. To accomplish this, perform the following procedure:

Vehicle and Applicator Tool Preparation

1. The evaporator core must be dry. This may be accomplished by disabling the compressor and running the blower fan on the recirc heat setting for an extended period of time.
Note: Compressor engagement will cause the evaporator core to remain wet and will prevent full adherence of the Cooling Coil Coating to the evaporator core surfaces.

2. Verify that the air conditioning drain hose is not clogged and place a drain pan beneath the vehicle.

3. Place a protective cover over the carpet below the evaporator core.

4. Remove the cabin air filter, if equipped, and cover the opening prior to applying the Cooling Coil Coating, as the product may clog the filter. If the cabin air filter appears to have little or no remaining life, suggest a replacement to your customer.

5. If the HVAC module has a blower motor cooling tube, be careful NOT TO SPRAY THE COOLING COIL COATING INTO THE BLOWER MOTOR COOLING TUBE.

6. Attach the Flexible Applicator Pressure Spray Tool (J-43810–20A) to a compressed air line operating at 586 kPa (85 psi) to 793 kPa (115 psi).

7. Shake the bottle of Cooling Coil Coating well. Screw the bottle onto the cap on the applicator tool's pick-up tube.
Note: The pick-up tube is designed for 120 ml (4 oz) and 240 ml (8 oz) bottles and should coil slightly in the bottom of a 120 ml (4 oz) bottle.

8. Use one of the following three methods to apply the Cooling Coil Coating.
Important: If the Pressure Applicator Spray Tool (J-43810–20A) is not available, the Cooling Coil Coating is also available in an aerosol can (P/N 12377951 (in Canada, 10953503)).

Application Through Blower Motor Control Module Opening
• Remove the blower motor control module (blower motor resistor). Refer to the applicable procedure in SI.
• Clean any debris or foreign material from inside the HVAC module and on the evaporator core surface.
• Apply the Cooling Coil Coating directly to the evaporator core through the blower motor control module (blower motor resistor) opening.
• Use the flexible wand to direct the Cooling Coil Coating over the entire evaporator core and surrounding gasket surfaces.
• When the application is complete, install the blower motor control module (blower motor resistor).

Application Through Blower Motor Opening
• Remove the blower motor. Refer to the applicable blower motor removal procedure in SI.
• Clean any debris or foreign material from inside the HVAC module and on the evaporator core surface.
• Apply the Cooling Coil Coating directly to the evaporator core through the blower motor opening.
• Use the flexible wand to direct the Cooling Coil Coating over the entire evaporator core and surrounding gasket surfaces.
• When the application is complete, install the blower motor

Application Through a Hole in the HVAC Module
• If neither of the two previous application methods are available, it may be necessary to drill a hole in the HVAC module.
• Locate an area of the HVAC module between the blower motor and the evaporator core. Drill a 10 mm (3/8 in) hole in the HVAC module. Use caution to keep the drill clear of the evaporator core and the blower motor fan.
• With the air distribution vents closed and the blower motor fan speed on HIGH, insert the applicator tool into the hole and spray the Cooling Coil Coating into the airstream toward the evaporator core.
• Use a GM approved RTV sealant to plug the hole in the HVAC module.

9. After the Cooling Coil Coating application is complete, start and run the vehicle for approximately 10 minutes, with the compressor disabled, HVAC mode set to Recirculate/Max, heat set to full warm, blower motor fan speed on high, and one window open approximately 12 mm (1/2 in). This cures the Cooling Coil Coating onto the evaporator core surface.

10. While the engine is running, rinse the applicator tool with warm water to prolong the life of the tool. Be sure to spray warm water through the nozzle to rinse out any residual Cooling Coil Coating still in the capillary pick up tube, otherwise it will dry and clog the applicator tool. Also remove the small green valve from the bottle cap and rinse it thoroughly while rolling it between two fingers and then reinstall it. If this valve is clogged , the Cooling Coil Coating will not flow through the applicator tool.

11. Shut off the engine and enable the compressor again.

12. Verify proper HVAC system operation.

13. Remove the protective cover from inside the vehicle.

14. Remove the drain pan from underneath the vehicle.

15. Reinstall the cabin air filter if necessary.
 

Simon01

Member
Dec 5, 2011
116
DAS said:
OK, what is SI? Thanks.

SI is GM's Service Information site, where they pull labor ops, bulletins and TSB's. It is accessed through GM Global Connect. Advisors and Techs should have access to it at most GM dealers.
 

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