EI06007 - Loss of HVAC Blower Motor Speeds Except for Hight Speed or Inoperative, CJ2 Climate Control (EI Resolution)

This bulletin is being revised to provide field fix information. Please discard Corporate Bulletin Number 06-01-39-001B (Section 01 -- HVAC).

Some customers may comment that the digital display on the HVAC control head is inoperative or is blank. Turning the vehicle on or off, or pushing the "AUTO" and "OFF" buttons on the control head, or any other buttons on the control, does nothing. The customer may also comment about rare instances of unusual display behavior.

Based on technician feedback, GM Engineering has determined two possible causes for this concern:

IGN3 Relay

This concern has been identified in mid- to late 2004 model year vehicles. Test if the IGN3 voltage is present by using the Tech 2® to attempt communication with the control head.

1. With the vehicle ignition ON, use the Tech 2® to navigate to the climate control menu.
2. Press a button on the control head and observe the Tech 2® to show an instance of a button state change. The change on the Tech 2® indicates the voltage is present and proper.
3. If no button state change is observed on the Tech 2®, replace the IGN3 relay and test again.
4. If no voltage is observed, proceed with diagnosing a wire break or discontinuity and repair as necessary.

Locked Control Head Logic Circuit

For instances where the HVAC system appears to be off (no blower or mode/temp actuator control), the control head is most likely in a logic lock-up state. This can be corrected by disconnecting the vehicle's battery.

1. Disconnect the vehicle's battery.
2. Wait 3-5 seconds and reconnect the battery to fully reset the system.
3. If the control head does not come alive by disconnecting and reconnecting the battery, replace the control head. Be advised the control head may be requested back through the Warranty Parts Center (WPC). DO NOT SHIP ANY PARTS TO THE WPC WITHOUT AN OFFICIAL WPC REQUEST.

For vehicles repaired under warranty, use: