Inoperative Rear HVAC Controls and/or DTC B0150 (Replace Rear HVAC Control)

This bulletin is being revised to add service procedures and parts and warranty information. Please discard Corporate Bulletin Number 02-01-39-003 (Section 01 -- HVAC).

Some customers may comment on an inoperative rear climate control panel. The controls may appear to not respond or to have very slow response for approximately one minute from starting the vehicle with limited temperature or mode range of the control. Diagnostic Trouble Code (DTC) B0150 may be stored in History. Some customers may associate this condition with a recent servicing that required the battery to be disconnected

When the battery is disconnected from the vehicle for any reason, at the first key on the rear HVAC controller will reset and perform a test sequence, sweeping the temperature and mode doors to the full range of their travel. If during this test one of the rear HVAC module doors runs beyond the expected range, DTC B0150 will set. This code will disable the rear HVAC control. Due to production variances, the mode and temp doors may be traveling beyond their programmed range.

A revised rear HVAC controller has been released that eliminates DTC B0150 and has updated programming to allow for a greater expected range of motion.

Vehicles built in April 2002 or prior that exhibit the above condition may be repaired using the following procedure. Vehicles built during May 2002 may have been assembled with the revised auxiliary temperature control panel. On step 1 of the following procedure, confirm the part number on the sticker attached to the rear auxiliary climate control panel. If the revised part number from the chart below is already installed, this bulletin does not apply to that vehicle. Use the following procedure to replace the rear HVAC controller:

1. Remove the rear HVAC controller by reaching in from the cupholder on the back of the floor console and pushing the controller out.
2. Disconnect 1 electrical connector from the rear of the HVAC controller.
3. Connect 1 electrical connector to the revised HVAC controller.
4. Install the rear HVAC controller by pushing inward until fully seated.
5. Start the engine and allow approximately one minute for the system to run its initial tests. Confirm the proper operation of the rear controller.

Parts are expected to be available 7-19-2002 from GMSPO.

For vehicles repaired under warranty, use: