Instruments - Intermittent Tach Operation/Needle Stuck

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Bulletin No.: T-92-43
File in Group: 8
Number: 142
Corp. Ref. No.: 218302
Date: Jan. 1992


SUBJECT: INTERMITTENT TACHOMETER OPERATION OR TACHOMETER NEEDLE STUCK BELOW THE 0 RPM POINTER STOP

MODELS AFFECTED: 1992 ELDORADOS AND SEVILLES EQUIPPED WITH ANALOG INSTRUMENT PANEL CLUSTER (UY9)


Some early production 1992 Eldorados and Sevilles equipped with Analog Instrument Panel Cluster (IPC) option UY9 may experience a condition of intermittent tachometer operation or tachometer needle stuck below the 0 rpm pointer stop.

Figure 1:

This condition may be due to an internal cluster condition which was corrected at cluster date code 2061. (A VIN breakpoint is not available. The condition was corrected in production by October 15, 1991.) The date code appears on a blue sticker on top of the cluster near the cluster 16-way connector. The sticker will appear as follows:


^ The cluster date code is a Julian Date. The above example shows the 206th day of 1991 (2061).

Diagnosis/Correction:

1. If the needle is stuck on the right side of the pointer stop or is inoperative with engine running, replace the cluster. Refer to DSIB 92-I-1 for the exchange procedure.

2. If the tech needle is intermittent, check cluster date code and exchange the cluster if less than 2061.

3. If the date code is greater than 2061, look for other history or current trouble codes and check the connections for the tachometer lead from the distributor at the "C" terminal through C101 F2 to the cluster 16-way connector terminal B1. Refer to Section 8C1, page 8.

NOTE: Do not attempt to reposition the tachometer needle if the needle is to the right of the stop. The tachometer may operate; but if an intermittent condition reoccurs, the needle will again wrap around to the wrong side of the stop.


For warranty purposes use Labor Operation N4180 at.4 hour. Add.2 hour administrative allowance if a cluster exchange is required. For cases where diagnosis beyond checking the date code is required, you may claim from 0 to .3 hour as diagnosis time.

Please report via SEARCH any cases in clusters after date code 2061.