INOP. 4WD INDICATOR LIGHT/RWAL CODE 5 (INSTALL 4WD HARNESS)

Subject: INOPERATIVE 4-WD INDICATOR LIGHT/RWAL CODE 5 (INSTALL 4WD JUMPER HARNESS)

Model and Year: 1991 K1, K2, K3 TRUCK WITH RWAL

Some 1991 K pickups may experience the 4wd indicator light not operating as intended, or an RWAL code 5. An electrical feedback condition may exist during vehicle start-up and cause the front axle engagement switch to become inoperative. This may keep the 4wd indicator light from coming on while the truck is in 4wd, and it may not disable the RWAL system as intended when the truck is in 4wd. If the RWAL is activated while in 4wd, a diagnostic code 5 may 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, a jumper harness must be installed in addition to replacing the front axle engagement switch. Do NOT replace any RWAL system components.

Notice: Vehicles subject to Dealer Product Campaign Bulletin No. 0R20 may still experience this condition as well after campaign completion.

VEHICLES INVOLVED:

All 1991 K pickups prior to the following VIN breakpoints are subject.

Pontiac East Assembly: GMC: 1GTGK24K1ME523066 Chevrolet: 1GCGK24K8ME168557

Fort Wayne Assembly: GMC: 1GTDK14K3MZ519462 Chevrolet: 1GCDC14Z8MZ169739

Oshawa Assembly:

GMC: 2GTEK19K6M1532000 Chevrolet: 2GCHK39N1M1191788

SERVICE PROCEDURE:

Jumper Harness Installation

1. Locate the single purple wire and connector that join the 4wd harness and the engine harness. This will be between the distributor and the bulkhead behind the engine and will be most easily accessed from the top of the engine (Figure 1, view A, labelled Engine Harness Connector).

2. Disconnect the purple wire connector and connect the jumper harness to the appropriate ends of the two connector halves.

SERVICE PARTS INFORMATION

Part Number Description Quantity Application ---------- -------------------- -------- ----------- 12111734 4wd jumper harness 1 K1,K2,K3 15638264 front axle engagement switch 1 K1,K3,K3

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.