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BLOWER FAN STAYS ON WHEN CAR IS OFF??


daniel812

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98 SLS

After using my A/C, I shut off the car and the fan keeps blowing. I can go into a store and come out hours later and its still on. Once I put the key in the ignition and turn the key, the fan will turn off. I pulled my codes and have none. Any ideas would be great

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Newer GM vehicle have a optional 'after blow' configuration option. This is to prevent mold buildup in the AC system. This option can be turned on/ off using a GM Tech 2.

That being said, not sure if the 1998 had this option. My 2001 does. My after blow is set to 'on.'

More...GM offered retro fit kits to enable the after blow method on older GM cars. Maybe a flubbed kit was installed.

I know when I shut MY car off...the blower turns off. I may come by the car 45 minutes latter and I can hear the blower running. But it does not run for hours on end...

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Naw...its normal. Been set that way for years..

In the original post...the '45 minutes' was just simply a guess. Go to the GM online service manual. 45 minutes is what it is.

"Afterblow

If the A/C compressor has been on for at least 2 minutes, the HVAC control module (IPM) will go into afterblow to remove moisture from the HVAC module. The blower motor will be activated at medium speed 45 minutes after the ignition has been turned off. The battery must have 12 volts minimum and outside temperatures must be 21°C (70°F) for higher. Afterblow air will be delivered through the last mode setting made by the vehicle operator or automatic system. The afterblow operation can be turned on with the scan tool. It is not set by the factory."

Strange...maybe go bet on '45' Monday..

Anyway...should not run for hours on end..

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Hi Logan

VBG I'm thinking about turning on that option on the 01 Since I just changed the evaporator it may help dry it out I had a drain tube issue that didn't allow the water to drain out the evaporator box So it rotted out the e core

Jim

Document ID # 667813

2001 Cadillac DeVille

--------------------------------------------------------------------------------

Afterblow Enable Procedure

The afterblow mode can be enabled using the scan tool. The afterblow mode allows the blower motor to operate after the engine has been turned off. This operation of the blower motor dries the evaporator core, which reduces the amount of microbial growth which can create undesirable odors.

When the afterblow mode has been enabled the blower motor will operate at medium speed for 4 minutes after the engine has been turned off. The following conditions must be met for the instrument panel module (IPM) to operate the afterblow:

The outside air temperature must be at least 21°C (70°F).

The A/C compressor must operate for more than 3 minutes.

The engine must be turned off for at least 45 minutes.

The system voltage must be at least 12 volts.

Use the following procedure in order to enable the afterblow mode:

Connect the Scan Tool .

The ignition should be ON, but the engine should not be operating.

Select instrument panel module.

Select special functions.

Select miscellaneous test.

Select IPM recalibration.

Select YES to enable the afterblow.

The Scan Tool will recalibrate the IPM to enable the afterblow mode.

© Copyright General Motors Corporation. All Rights Reserved.

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Mine info is from GM document #701334. GM online..same the dealer uses..

I also know of your 'pinched' drainage system..they been set that way for years..like a slit in the end of the tube..

Air Delivery Description and Operation

The air delivery controls are divided into 7 primary areas:

• HVAC Control Components

• Air Speed

• Auxiliary Air Speed

• Air Distribution

• Auxiliary Air Distribution

• Recirculation Operation

• Automatic Operation

HVAC Control Components

HVAC Control Module

The HVAC control module (IPM) is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The dash integration module (DIM), which is the vehicle power mode master, provides a device on signal. The control module (IPM) supports the following features:

Feature

Availability

Afterblow

Yes

Purge

Yes

Personalization

Yes

Actuator Calibration

Yes

Heated Seat Control

No

The HVAC control module (IPM) will receive information that defines the current driver of the vehicle from the driver door module (DDM) through class 2 communication. The HVAC system will memorize the following system configurations for up to two unique drivers:

• Driver set temperature

• Passenger set temperature

• Mode

• Blower motor speed

• A/C compressor request, auto ON or A/C OFF

This information shall be stored inside the HVAC control module (IPM) memory. When a different driver identification button is selected the HVAC control module(IPM) will recall the appropriate driver settings. When the HVAC control module (IPM) is first turned on, the last stored settings for the current driver will be activated except for the rear defrost.

Mode and Recirculation Actuators

The mode and recirculation actuators are 2-wire bi-directional electric motors. Two control circuits enable the actuators to operate. The control circuits use either a 0 or 12 volt value to co-ordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 12 volts. In order to move the actuator, the HVAC control module grounds the appropriate control circuit for the commanded direction. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction.

The HVAC control module(IPM) determines the door position by counting motor pulses on one of the control circuits. These pulses are small voltage fluctuations that occur when the brush is shorted across two commutator contacts as the motor rotates. As the actuator shaft rotates, the HVAC control module(IPM) monitors the voltage drop across an internal resistance to detect the pulses. The HVAC control module(IPM) converts the pulses to counts with a range of 0-255 counts. The HVAC control module(IPM) uses a range of 0-255 counts to index the actuator position.

Auxiliary HVAC Control Module

The auxiliary HVAC control module (IPM) is a class 2 device that interfaces between the operator and the auxiliary HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The dash integration module (DIM), which is the vehicle power mode master, provides a device on signal.

Auxiliary Mode Actuator

The auxiliary mode actuator is a 3 wire bi-directional electric motor. Supply voltage, low reference and control circuits enable the actuator to operate. The control circuit uses a 0-12 volt linear ramped signal to command the actuator movement. The 0 and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between 0 and 12 volts correspond to the positions between the limits.

Air Speed

The blower motor forces air to circulate within the vehicle's interior. The vehicle operator determines the blower motor's speed by placing the blower motor switch in a desired speed position or by selecting automatic operation. In manual operation, once a blower speed is selected, the blower speed remains constant until a new speed is selected. In automatic operation, the HVAC control module(IPM) will determine what blower speed is necessary in order to achieve or maintain a desired temperature.

As the requested blower speed increases, the following conditions occur:

• The HVAC control module(IPM) increases the amount of time that the blower motor speed control circuit is modulated to ground.

• The voltage and duty cycle, measured between the blower motor speed control circuit and ground, decrease.

As the requested blower speed decreases, the following conditions occur:

• The HVAC control module(IPM) decreases the amount of time that the blower motor speed control circuit is modulated to ground.

• The voltage and duty cycle, measured between the blower motor speed control circuit and ground, increase.

Steering Wheel Controls

The HVAC control module(IPM) receives class 2 messages that the driver has activated a steering wheel control switch from the dash integration module. The HVAC steering wheel control button controls driver set temperature increase and driver set temperature decrease.

• Fan speed increase

• Fan speed decrease

• Driver set temperature increase

• Driver set temperature decrease

The HVAC system interprets the set temperature switch on the steering wheel as if the driver had activated the same switch function on the HVAC control module (IPM).

Afterblow

If the A/C compressor has been on for at least 2 minutes, the HVAC control module (IPM) will go into afterblow to remove moisture from the HVAC module. The blower motor will be activated at medium speed 45 minutes after the ignition has been turned off. The battery must have 12 volts minimum and outside temperatures must be 21°C (70°F) for higher. Afterblow air will be delivered through the last mode setting made by the vehicle operator or automatic system. The afterblow operation can be turned on with the scan tool. It is not set by the factory.

Auxiliary Air Speed

The auxiliary blower motor provides additional airflow for the back seat passengers. The auxiliary blower motor will operate as long as the HVAC control module is ON. Passengers can operate the system in both manual or automatic modes. The only time the auxiliary blower motor is not available is when the HVAC control module (IPM) is in FRONT DEFROST. The auxiliary blower motor icon will flash to indicate that the blower is not available. Power is provided to the auxiliary blower motor from the rear fuse block. Depending upon selected blower speeds, ground is either supplied directly to the blower motor or voltage is varied by a series of in-line resistors on the ground side of the circuit.

Air Distribution

The HVAC control module(IPM) controls the mode actuator in order to distribute airflow to a desired outlet. The mode switch provides the vehicle operator with the ability to override the automatic setting. When the mode door is moved to the defrost position, the A/C compressor clutch engages and the recirculation actuator will be moved to the outside air position.

Auxiliary Air Distribution

The auxiliary HVAC control module controls the auxiliary mode actuator in order to distribute airflow to a desired auxiliary outlet.

Recirculation Operation

The HVAC control module(IPM) controls the air intake through the recirculation actuator. Recirculation is not available when the mode is in defrost.

Automatic Operation

In automatic operation, the HVAC control module (IPM) will maintain the comfort level inside of the vehicle by controlling the A/C compressor clutch, the blower motor, the air temperature actuators, mode actuator and recirculation.

To place the HVAC system in automatic mode, the following is required:

• The blower motor switch must be in the AUTO position.

• The air temperature switch must be in any other position other than 60 or 90 degrees.

• The mode switch must be in the AUTO position.

Once the desired temperature is reached, the blower motor, mode, recirculation and temperature actuators will automatically adjust to maintain the temperature selected (except in the extreme temperature positions. The HVAC control module (IPM) performs the following functions to maintain the desired air temperature:

• Monitors the following sensors:

- Inside air temperature sensor

- Ambient air temperature sensor

- Upper duct sensors

- Lower duct sensors

- Sunload sensor

• Regulate blower motor speed

• Position the air temperature actuator

• Position the mode actuator

• Position the recirculation actuator

• Request A/C operation

When the warmest position is selected in automatic operation the blower speed will increase gradually until the vehicle reaches normal operating temperature. When normal operating temperature is reached the blower will stay on high speed and the air temperature actuators will stay in the full heat position. When the coldest position is selected in automatic operation the blower will stay on high and the air temperature actuators will stay in the full cold position.

In cold temperatures, the automatic HVAC system will provide heat in the most efficient manner. The vehicle operator can select an extreme temperature setting but the system will not warm the vehicle any faster. In warm temperatures, the automatic HVAC system will also provide air conditioning in the most efficient manner. Selecting an extreme cool temperature will not cool the vehicle any faster.

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Logan IS this INFO for an 01 ? Some of the opotions are don't appear until later model cars Just curious

On the MI lotto you have to bet more that 2 numbers I may use 45 in the mega millions lotto as one of the numbers

Jim

That is the current document..GM online...for a 2001 Cadillac Deville. Up to date GM info.

I copied the header:

Document ID# 701334

2001 Cadillac DeVille

Mine...appears to work exactly as described. 45 minutes.

I walk by and don't think about it. But I know whats up.

Maybe 454 ...0r 4554. I very rarely play. I see someone got the big one...it would ruin your life..IMO.

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Hi Logan

Just curiuous Did you ever have to replace the blower motor? I have been thinking of turning on the afterblow feature I have the original blower motor & I'm thinking it's a little long in the tooth to run that feature The blower motor is easy to chage in the 01's I don't feel like changing anymore parts for awhile after that evaporator coil I don't feel like going back into the dash for awhile I hope the dealer turns up a nice 07dts QUICK The dealer called last friday I didn't return his call He has some 07's that came in I need to go to the dealer in the morning for a part I need to chage the rubber drain on the evaporator drain that little rubber elbow is what caused my evap core to rot out the end of the rubber was pinched together not allowing the water to drain I have been keeping an eye on it yesterday & today it drips but NOT much You would think with a new evaporator it would be dripping like crazy So I will order the part in the morning

Thanks

Jim

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No, havent changed one on these models. Should be must easier then the older cars.

Anyway, just looked it up. The 1998 DOES have afterblow command available.:

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:

HVAC afterblow enable procedure.

Recommendation/Instructions:

1998-03 Cadillac Seville, 2000 Cadillac Deville

Connect the Scan tool.

Turn ON the ignition, with the engine OFF.

Select Instrument Panel Module.

Select Special Functions.

Select miscellaneous test.

Select IPM recalibration.

Select YES to enable afterblow.

SI. Document number 667536

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

That being said. Afterblow can come on at strange times...but should not blow for hours at a time. Maybe 10 minutes..

So for lottery...maybe 4510. Hmmm

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Hi Logan

Actually I like the older design better it's easier to change the blower motor & evaporator cores on the devilles if you know how it's all in the eng compatment on the firewall

On the 2000 forward it's inside under the dash THAT sucks

Jim

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If you remember...maybe a year ago. I had a imbalance in the front AC. Couple of hours wasted. Find out in some fine GM print it indicated that the freon was low. True. At that time I also noticed that it would be a dash pull out to replace some of the AC system.

Blower is easy. Everything else XXX .

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Logan

VBG You got that rite the blower is easy The rest of the ac & hvac is buried in the dash GM didn't make it easy to get at some parts

On Saturday I was calling the guy who engineered the ac system everything but a white man

Jim

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And in the end, that was the correct choice.

What Logan pasted is the same thing as "whoever" posted earlier in this thread, it just depends on how you read the sentence. The GM online manual that Logan posted does not tell you how long the motor should run, only that it should start in 45 minutes.

Never underestimate the amount of a persons greed.

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In the above post chnage "whoever" to JIMDTS. I can't review posts a page back when posting.

Never underestimate the amount of a persons greed.

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