Dead speedo

[m20e30]

Is there a known problem / weakness with the speedo on the E30? I have an '87 325is and the speedo was acting flakey for a few weeks and then died - tach and other gauges still work fine. I know the prevous owner changed the instrument cluster because I found a receipt for a used one amongst the paperwork he gave me. I think it might be a wiring issue. How can I test the sender & wiring?

Thanks

[strad]

I have read that the speedometer gears are the issue usually. They are located on the cluster. I don't know about your question -- Bentley probably has specs for the sender/wiring though.

edit: damn reading comprehension! jlevie is right about the gears, and I knew that factoid as well, just didn't come out right. G/L.

[jlevie]

The plastic odometer gears will fail in time but they don't affect the speedometer. Based on the description of the problem and how it developed I'd bet on the speed sensor being bad.

[Bmjpv]

Cluster gears

I've found after many years of VDO speedhead repairs that pushing the reset button ONLY when the car is stopped will greatly extend the life of these internal gears . joe

[dark89e30]

Yeah, I have the same problem. It started after I replaced the cluster due to a different board issue and now the new one in there has the same issue. Rule out the VSS, odo gears, and buy yourself a speedo. This is a common issue on these.

[JoeP]

Will it start working if you smack the dash? I had one that would die but if I hit the dash it would come back for a while. It had a bad solder joint on the main board. I changed it out and it worked perfectly.

[Court M3]

check the speedo sensor. Get a cheap one from the junkyard and swap them out.

[m20e30]

Dead speedo

Thanks all for the input. I'll check the sender etc. before pulling it out.

[Coco Savage]

so my speedo and mileage counter dun work? would this be a diff prob?