Some 1988 and early production 1989 C/K Trucks may experience a reduced air flow condition at the upper right side defroster outlet during the defrost operation. This condition is due to an insufficient amount of air flow directional vanes within the windshield defroster nozzle assembly. To address this condition, three (3) vanes have been added to the inside of the defroster nozzle assembly (P/N 15530575) to redirect the air flow (See Figure 1).
Parts are currently available from CANSPO.
Beginning with the following VIN breakpoints, the redesigned defroster nozzle assembly was incorporated into production.
Fort Wayne GMC KZ514997 Chevrolet KZ151827
Pontiac East GMC KE517470 Chevrolet KE156690
Oshawa GMC K1522243 Chevrolet K1150679
For repair to vehicles under warranty, use the applicable Labour Operation and Time:
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.