Instrument Cluster - Bulb and Odometer Troubleshooting

GROUP 62
Instruments



Bulletin Number
62 02 89 (1828)



Woodcliff Lake, NJ
April 1989
Technical Dept.



SUBJECT:
Instrument Cluster - LCD Display Module

MODELS:
E32, E34

Observation:
It has been found, through examination of returned LCD Display modules, that the majority are not defective.

Situation # 1:
A large portion of those found to be non-defective however, did have burnt out illumination bulbs.

Contained within this module are the

^ Odometer and trip odometer displays

^ Check Control dot matrix display

^ Service Interval Indicator display

^ Transmission range and mode displays

A burnt out bulb for this module will result in the partial or non-illumination of one of these displays.

Whenever such a complaint is received use the BMW Service Tester to perform the System Test for the Instrument Cluster.

During this test all segments of the display will be activated. The display module should only be replaced if there are missing segments of the odometer numbers or dot matrix displays.



To gain access to these bulbs, along with the bulbs for the gauge backlighting, remove the cluster.

Turn the locks to the open position.



Situation # 2:
It was also discovered the LCD modules have been replaced for complaints relating to the odometers; i.e. mileage jumps, trip odometer resets when turning the ignition OFF.

Please be aware that the LCD Display Module contains no logic functions and has no memory capabilities (odometer).

It only displays information that is transmitted to it via various components within the vehicle and the instrument cluster.



^ The memory for the odometer is retained within the coding plug.

^ The memory for the trip odometer is retained within the main circuit board.

Warranty
Information:
Warranty claims will not be paid if the returned LCD module is not defective.

Reimbursement for defective/burnt-out bulbs is covered under the terms of the BMW New Car Limited Warranty of 12 Months/12,000 Miles.