Unofficialbmw.com

[PJK]

My Instrument cluster has become next to useless. Intermittantly all of the functions controlled by its internal electronics stop working. After each event the trip mileage is reset. While the regular odometer goes dark it comes back to a number similar to that before the event. I haven't yet noted if it accumilates mileage during the dark period.

Anyone else see this? What was the solution?

Thanks,

Phil

[Zyggy]

could be lose connections or burnt out bulbs

Here are some good instructions:

http://www.pelicanparts.com/bmw/tech...-90-Gauges.htm

[PJK]

I don't think it is the bulbs as all the gauges also fail at the same time.

I am guessing a bad solder connection in the pc board.

I am now in the process of dissconnecting the babykiller electronics so I can remove the cluster and power it up as I flex the board. Disconecting the cluster with power on will set a baby killer fault as will powering up the car with the steering wheel removed.

Phil

[PJK]

I still have the instrument cluster gremlen, but I have made some progress. I did have to remove the baby killer electronics to get to the connector. It is mounted behind the glove-box with tamper resistant bolts.
With the steering wheel removed and the cluster powered up it did screw-up. I smacked it with a screwdriver handle and it came back to operation.
This gives some credability to the notion that the fault is in the cluster. The display seemed to become solid so I replaced the cluster and the baby killer but I put a power switch on the baby killer. Now if I need to remove the steering wheel I can simply turn off the switch to disarm the baby killer. I tested it on and off several times and no fault. When it is on the light flashes as the ignition switch is turned on. All cars with these infernal things should have this switch.

Phil

[Casey3561]

So you're saying yours had to do with a relay behind the glovebox?

Can you walk me through how to fix this? Mine has the same problem- a 93 318is- and replacing the cluster with a used one didn't help. The connectors are clean and the frequency of the error has lessened since it was replaced, but it's still there.

[PJK]

Hi Casey,

The thing behind the glovebox is the airbag electronics. It must be disarmed before working on the instrument cluster or a fault which must be cleared by the dealer will be set. If your car is a late '93 the airbag electronics may be under the rear seat.

With all the airbag stuff removed I dissembled the cluster and powered it up in the car. Of coarse all the gauges were missing at this time but the odometer and the failing lights were still there. I could not find any bad solder and flexing the board could not make the problem come and go. I reassembled the cluster and powered it again. It did screw-up. I tapped it with a screwdriver handle. It started to work again. This makes me think that the problem is in the cluster.

I reassembled the car but I put a switch on the air bag system so now I can just turn it off and remove the air bag from the steering wheel, remove the steering wheel and get to the cluster without messing with the glove compartment.

Next step is to dissemble the cluster further. There are some heat staked plastic posts securing the PC boad to the rear cover. I will have to cut off the melted plastic and figure a new way to secure the board. After removing the board I will be able to inspect the side of the board which I did not see last time. If I don't find anything I will attach wire leads to all the power supply and ground lines and reassemble everything. I will connect an array of light bulbs to the wires to monitor the supply lines and grounds. If the lights stay on as the cluster screws - up, I will conclude that the cluster has a problem. Speedometer shops will exchange it for about $300. That is a lot but it beats about $800 at the dealer.

Phil