| Subject: | Blower Motor Inoperative or May Not Shut Off in Extremely Low Ambient Temperature Conditions (Replace Blower Motor Control Module) | 
| Models: | 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) | 
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).
Some customers may comment that the blower motor is inoperative or continues to run after the vehicle has been shut off.
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.
Important: Replace the blower motor control module if the vehicle experienced a blower motor control module failure in extremely cold ambient temperature conditions.
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.
Part Number  | Description  | Qty  | 
|---|---|---|
89018849  | Module Assembly, Auxiliary Blower Motor Control (Rear System on Escalade ESV, Suburban, Yukon XL)  | 1  | 
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  | 
For vehicles repaired under warranty, use:
Labor Operation  | Description  | Labor Time  | 
|---|---|---|
D0890  | Module, Blower Motor Control - Replace  | Use Published Labor Operation Time  | 
Add  | Diagnostic Time  |