Headlamps/Interior Lights Dim Intermittently in Cold Weather (Replace Generator)

This bulletin is being revised to add the 2002 model year and include additional information on a similar condition which may exist in this vehicle. Please discard Corporate Bulletin Number 01-06-03-007 (Section 06-Engine).

Important: Short term voltage drops (flickers/fluctuations of lights) may occur whenever high demands are placed on the vehicle's electrical system. This is considered a normal generator output characteristic and a repair may not be necessary.

Some customers may comment on an intermittent condition in which the headlamps or interior lights may dim in cold weather. This condition may also be noted in the blower speed slowing or changing pitch intermittently.

This condition may be caused by intermittent low voltage. Transient engine vibrations may induce the generator to experience field discontinuity. This state results in a voltage spike that causes the voltage regulator to reset. During this period, the electrical system drops to battery voltage.

Important: During voltage regulator reset, at no time will the headlamps go out.

An improved generator assembly is now available from GMSPO.

Important: All 2001-02 3.5L V6 Auroras are equipped with an electric AIR pump. After generator replacement, these vehicles may still exhibit very short voltage dips and/or headlamp dimming due to the AIR pump cycling. Once the generator has been replaced, any short term voltage drop should be considered normal. If the customer returns a vehicle that has been corrected with a generator replacement, you may reassure the customer by demonstrating the condition. Refer to the following AIR Pump Demonstration section.

Replace the existing generator with a revised generator assembly, P/N 10464486.

Refer to the Generator Replacement LX5 procedures in the Engine Electrical sub-section of the Service Manual. Within SI, refer to document ID 619734.

1. Using the Tech 2® Diagnostic scan tool, connect the DLC connector to the vehicle and establish communications.
2. After entering the vehicle information, select the Powertrain option.
3. Select the Special Functions menu.
4. Select Engine Output Controls.
5. Select the AIR system.
6. From this screen, you may command the AIR pump on and off. Turn the headlamps on. You will now be able to verify the condition that was the customer concern. Demonstrate the headlamp dip during this normal operation of the pump and reassure the customer that this is a normal condition.
7. Exit the Tech 2® and disconnect the DLC connector.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: