Campaign - 4X4 Indicator Light Wiring: Overview

90chevy37

Number: 91C07


Section: 8B


Date: Nov., 1990


Subject: PRODUCT CAMPAIGN 91C07 4WD INDICATOR LIGHT WIRING


Model and Year: 1991 CHEVROLET K 1500-3500 SERIES PICKUP TRUCKS (OSHAWA ASSEMBLY CENTRE ONLY)


TO: ALL CHEVROLET DEALERS


General Motors has determined that on certain 1991 Chevrolet K 1500-3500 Series Pickup Trucks built at the Oshawa Assembly Centre the front axle indicator light may not work as intended. An electrical feedback condition may allow the light to remain on when the transfer case is shifted from four-wheel drive (4wd) to two-wheel drive (2wd). If the vehicle continues to be operated in 2wd, this feedback condition will fail the front axle engagement switch causing the light to go out. When the vehicle is again placed into 4wd, the light will not go on and the rear wheel anti-lock (RWAL) system will remain enabled (it is normally disabled in 4wd). If the RWAL is activated while in 4wd, a diagnostic code "5" will be set in the RWAL module. This disables the RWAL function and causes the brake warning light on the instrument panel to illuminate and remain on.


To correct this condition, dealers will install a new wiring harness and front axle engagement switch on all involved vehicles.