MANUAL UPDATE SEC. 8A-81 INSTRUMENT PANEL GAUGE TACH.

MODELS/YEARS 1985-89 CUTLASS CIERA

The text included in Section 8A-81 of the 1985 through 1989 Cutlass Ciera Service Manuals should be replaced wfth the new diagnosis information. Please insert the following text in your copy of the 1985 through 1989 Service Manuals.

TACHOMETER DIAGNOSIS

1. Get the J33431 instrument Panel Cluster Tester and connect the J33431-10 harness connector to the J33431.

2. Disconnect the connector to the Ignition Module which contains the Tachometer wire (See Schematic).

3. Connect the black lead of the J33431-10 to ground and the red lead to the Tachometer lead of the ignition Module Connector (See Schematic).

4. Plug the J33431 into a nearby 120 volt outlet.

5. Set the Tester Frequency Signal Switch to 6OHz and Power switch to ON.

6. Put the vehicle ignition Switch in RUN and observe the Tachometer.

If the Tachometer shows 1350 rpm (6cy) or 1800 rpm (4cy), replace the suspect Ignition Module.

If the Tachometer does not operate, check the wire to the Tachometer for an open or short to ground. Check that the Instrument Panel Cluster Connectors and the screw connections at the back of the cluster are clean and tight. If all of the above are OK, replace the Tachometer (See Section 8C for remove/replace procedures).

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.