WHISTLE NOISE FROM BLOWER - MODIFY BLOWER CASE

SUBJECT: WHISTLE NOISE FROM BLOWER MODIFY BLOWER CASE

VEHICLES AFFECTED: 1990 J, N, L

Some 1990 J, N, & L vehicles built between the VIN breakpoints listed below may exhibit a "whistle" noise when the blower is operated under certain conditions. The whistle noise may be experienced under the following operating conditions:

With A/C Without A/C

- High Blower Speed Only - High Blower Speed Only - Max AC Mode - Bi-Level Mode - Norm AC Mode - Vent Mode - Bi-Level Mode - Temp Lever Set to Full - Vent Mode Cold Position - Temp Lever Set to Full Cold Position

VEHICLE BREAKPOINTS

J Car

All With or Without AC Plant Nameplate From VIN to VIN

Janesville Chevrolet L4 LJ223934 - LJ249597 Janesville Chevrolet V6 LJ223934 - LJ255087 Lordstown Chevrolet L4 L7159861 - L7168602 Lordstown Chevrolet V6 L7160654 - L7168602 Lordstown Pontiac L7585550 - L7601686

N Car Without AC With AC ------------- -------- Plant Nameplate From VIN to VIN From VIN to VIN

Lansing Pontiac LC317136 LC346000 LC320480 LC346000 Lansing Oldsmobile LM748734 LM759966 LM749377 LM759966 Lansing Buick LM050035 LM060946 LM050700 LM060946

L Car

All With or Without AC Plant Nameplate From VIN to VIN #

Linden Chevrolet LE193605 LE202697 Wilmington Chevrolet LY199448 LY213672 Wilmington Pontiac LY707717 LY710317

In order to reduce the whistle noise the following procedure should be used. The procedure for N is different than for J & L and is listed below for each carline.

N Car

1. Remove blower motor and fan assembly from vehicle. 2. Locate tab (Figure 1) inside blower motor case. 3. Bend tab downward about 20 degrees as shown in Figure 1. 4. Install previously removed motor and fan assembly.

J & L Car

1. Same as above. 2. Same as above. 3. Same as above. 4. Replace blower motor assembly using kit P/N 22098839 with some modifications as listed: - Do not use spacer provided in kit - Do not use long screws provided in kit - Do not use extended blower motor cooling tube

5. Using the fan nut provided in the kit, install original fan on new motor assembly.

6. Install blower motor/fan assembly on vehicle.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.