Blower is crazy

Tiny
BGRAHAM5
  • MEMBER
  • 2006 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 152,000 MILES
My 2006 chevy Trailblazer's heat/airconditioner is doing what it wants. Some times it doesn't come on when I turn it on, and some times it comes on by itself. If it comes on, the blower continues to run even when the suv is turned off. It will run all night/day until it drains the battery. Please tell me what I should try, or look at.
Thanks
Sunday, January 23rd, 2011 AT 7:56 PM

12 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
There is a tech bulletin on this, it is as follows:
Blower Motor Inoperative or May Not Shut Off in Extremely Low Ambient
Temperature Conditions (Replace Blower Motor Control Module)
TECHNICAL SERVICE BULLETIN
Reference Number(s): 06-01-39-002C, Date of Issue: January 18, 2008
Related Ref Number(s): 06-01-39-002, 06-01-39-002A, 06-01-39-002B, 06-01-39-002C
ARTICLE BEGINNING
CONDITION
Some customers may comment that the blower motor is inoperative or continues to run after the
vehicle has been shut off.
CAUSE
These conditions may be caused by a blower motor control module failure. This failure may occur
when the vehicle is operated in ambient temperature conditions of -23°C (-10°F) or below.
CORRECTION
Technicians are to replace the blower motor control module, also called the Linear Power Module
(LPM), with the P/N listed below. Refer to either the Blower Motor Control Processor Replacement
or Blower Motor Processor Replacement-Auxiliary procedures in SI. After replacement of the blower
motor control module, the customer may notice a slightly higher than expected blower motor speed at
any of the blower speed settings.
PARTS INFORMATION
Parts Information
Press Ctrl+F to find exact text
Affected
Model(s):
2004-2007 Buick Rainier; 2003-2006 Cadillac Escalade Models; 2003-2006 Chevrolet
Avalanche, Silverado, Suburban, Tahoe; 2003-2007 Chevrolet TrailBlazer Models;
2007 Chevrolet Silverado (Classic); 2003-2006 GMC Sierra Models, Yukon Models;
2003-2007 GMC Envoy Models; 2007 GMC Sierra (Classic); 2003-2004 Oldsmobile
Bravada; 2003-2006 HUMMER H2 Models; with Automatic Temperature Control
HVAC System (RPO CJ2)
Supercedes:
This bulletin is being revised to update the model years that are affected and add the
Oldsmobile Bravada. Please discard Corporate Bulletin Number 06-01-39-002B
(Section 01 - HVAC).
IMPORTANT: Replace the blower motor control module if the vehicle experienced a
blower motor control module failure in extremely cold ambient
temperature conditions.
Part Number
Description
Qty
89018849
Module Assembly, Auxiliary Blower Motor Control (Rear System on
1
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Warranty Information
Escalade ESV, Suburban, Yukon XL)
89018964
Module, HTR & BLO & A/C CONT (Front system only vehicles -
Except H2)
1
89023355
Module Assembly, Blower Motor Control (H2 Models)
1
89024926
Module Assembly, Auxiliary Heater & A/C Control (Rear System on
Escalade, Yukon, Tahoe)
1
Labor Operation
Description
Labor Time
D0890
Module, Blower Motor Control - Replace
Use Published Labor
Operation Time
Add
Diagnostic Time
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Sunday, January 23rd, 2011 AT 8:00 PM
Tiny
BIZLEY
  • MEMBER
  • 2 POSTS
  • 2006 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 135,000 MILES
Blower fan stays on when vehicle turned off. Removed fuse for temporary fix
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
So do you have auto climate control or manual controls?Also do you have a multi meter to do some testing?
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
BIZLEY
  • MEMBER
  • 2 POSTS
Manual controls and no current testing ability
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
We are going to have to do some testing and thats your part since iam not there with I can only guide you along.
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
FIREMAN2ASST
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 75,000 MILES
The heater in my truck is one that has the digital readout with the dual climate controls. I can also control the climate with a button on the steering wheel. Starting recently, the fan will not kick up to a higher speed than low even though as I am pushing the button up, the speed meter on the readout goes up with it, but no fan speed change. Same when I use the button on the steering wheel. Meter goes up, no fan speed change. Then, when I shut my truck off, the blower fan continues to run on low even after I exit my vehicle for another minute or 2. Does this mean that the face plate for the heater controls has gone bad or is it something worse?
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
DENNYP
  • MECHANIC
  • 1,824 POSTS
You need to replace the blower motor control module.


https://www.2carpros.com/forum/automotive_pictures/102900_blower_2.jpg



1) Blower Motor Control Processor
(2) Blower Motor
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
RICHARDSON61
  • MEMBER
  • 2 POSTS
  • 2004 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
The blower motor continues to run even after car is turned off. Have to pull fuse to get it to stop. Would this be a problem with the control switch or the resistor?
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Hello, does it still run if the blower speed switch is turned off? Hvac controls off?
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
RICHARDSON61
  • MEMBER
  • 2 POSTS
Yes, it continues to run no matter what position the swithc is in or whether or not the car is on or off
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
It sounds like the blower relay is stuck here is a the location and a guide to help you test it.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)
Tiny
BROWNN
  • MEMBER
  • 1 POST
Thanks for the post I had this problem and had to get a new relay, cost me $34.00
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Tuesday, June 4th, 2019 AT 6:48 PM (Merged)

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