Erratic Speedometer

[rayncc]

The speedometer on my car (E30 M40) has been erratic of late, sometimes working sometimes not. When it's not working, the odometer and the fuel consumption gauge stopped functioning as well.I would welcome feedbacks from fellow owners who experienced and rectified this problem to give me advise on what is the root cause?If the problem lies with the meter, is there any mechanic who undertakes such repair? I would prefer to retain my existing meter instead of replacing it with a used unit. Cheers..

 

[bimmerholic]

why not try the cheapest method of "fix"? Open your cluster, remove and fiddle and tuck all the socket in securely. It might help.

 

[mizhan]

check all connections of the bunch of wires under the carpet of front passenger floor.

 

[rayncc]

Guess the problem is confined to the meter coz when i tapped it, the meter will flicker momentarily. Hmm...will take it out to inspect

 

[schwa]

open the meter,resolder the board. mine was fixed that way. hope it helps

 

[warfield]

Dear Rayncc... have you resolved the problem?? Eventually I encounter the same problem..

 

[virtualmystic]

Try replacing the battery in the instrument cluster. Its a rechargeable AA size battery and may be replaced with a modern rechargeable AA battery. The battery is mainly used for the service lights but it has been observed that a weak battery may also cause erratic speedometer and odometer readings.

 

[warfield]

Dear Virtual,

Tq for the response, any tips on how to do it DIY. Still new to BMW.. tq in advance.

 

[rayncc]

Dear Rayncc... have you resolved the problem?? Eventually I encounter the same problem..

Hi Warfield,

Nope, have not fixed my yet. Been procrastinating coz not sure how difficult it will be to open up speedo and reinstall. Anyway will surely give it a try...

 

[virtualmystic]

removal of the instrument cluster is quite easy. Once you have done it once, it might take you about 10 minutes to do it the next time. The problem will be opening up the cluster. Some screws might be too tight to remove after all these years. Once the battery i saccesible you can take it to some electronic shops who will be able to help you solder in a new battery.

 

[schwa]

http://www.beckerelectronics.com/SIboard/siboard.html

 

[virtualmystic]

Thanks for the confirmation. I had read about this years ago and probably also in my Haynes manual. Not really sure where it was I got the information but it sorta stuck in my gray cells. hahaha! If you want help withthe removal of your instrument cluster I will be glad to help. Just PM me.

 

[rayncc]

Update

Opened up the meter just now and my brother-in-law helped to solder the board behind the speedometer. Brush the connectors to clean it before fixing back the speedometer to its housing. Did not attempt to open up the batteries on the lower board. Fixed back the meter and viola, it works fine!!
Hope it will remain so...

 

[Aero]

Hi Virtual

Any idea on what are the spec of type of battery needed for the replacement.

Thanks

 

[virtualmystic]

Hi Virtual

Any idea on what are the spec of type of battery needed for the replacement.

Thanks

It is an AA size battery (single) that produces 1.2 volts. I do not know the capacity (in mAh) but any modern rechargeable AA battery would suffice.

 

[warfield]

Hi all,

Just to share my experience, actually my car is still under the warranty of the used car dealer. So i asked them to fix the problem of erratic speedometer. Here are the list of things done in attempt to fix it:

1. Change the sensor located at the tyres (can't remember what sensor is it) - works for only few hours.. and the problem came back;
2. Change ABS Sensor - only work for few hours only.. proble came back;
3. Cleaning up and solder the Instrument Cluster (I advice them to do so based on the proposed actione in this forum) - same also.. last for few hours only;
4. Lastly.. change ABS pump... ( so far my speedometer works fine) hope to last longer continuously...

Cheers