You have to install a capacitor. Here is a bulletin. Subject: Blower Motor Inoperative or Intermittent, Blower Speed May Drop or Blower Continues to Run After Key Off (Install a Capacitor at Blower Motor Control Module Connector)
Models: 2005 Buick Allure (Canada Only), LaCrosse
2004-2005 Pontiac Grand Prix Some customers may comment on an inoperative or intermittent Heating, Ventilation and Air Conditioning (HVAC) blower motor. Others may comment that the blower motor speed may momentarily drop or that the blower motor continues to run after the key is turned off.
Disconnect the negative cable from the battery. Refer to the Battery Negative Cable Disconnect/Connect procedure in the Engine Electrical section of SI.
Remove the right closeout/insulator panel. Refer to the Closeout/Insulator Panel Replacement-Right procedure in the Instrument Panel, Gages and Console section of SI.
Disconnect the wire harness connector to the blower motor control module. Start here
Monday, May 26th, 2008 AT 7:18 PM