Help speedo issue

[bhaza]

Hi when driving car the speedo will stop working it sometimes bounces and then just starts to work again anyone have any ideas as to what can cause this please?

Thanks

[rich318i]

not had that problem let myself YET! lol

[toby]

Often a break in the speedo wiring which ends in a little plug on the differential. Have a little look and check the plug/wiring is not loose or damaged.

[Brianmoooore]

The break in the wire is often not visible, as the cause is a change in the crystalline structure of the copper conductor of the wire caused by vibration from the diff. This makes the copper brittle, and the wire breaks inside the plastic sheath, without any damage to this sheath.
The break can be found by gently stretching the individual wires, but it's important that at least the last 300mm of wire to the diff. is replaced, complete with plug, as any repair will still leave the remaining copper in the brittle state. A suitable plug and length of wire can be found around the headlamp area on a scrap E30 loom, or a repair cable can be bought from BMW.

[jmc330i]

Hi when driving car the speedo will stop working it sometimes bounces and then just starts to work again anyone have any ideas as to what can cause this please?

Thanks

Does the odometer still turn when the speedo stops?

I'm having this problem with mine, but with the odometer still working I'm guessing its a problem with the clocks, rather than the usual wiring at the diff.

[Brianmoooore]

Speedo and odometer circuitry are all contained on a small circuit board behind the speedo, so your problem is most probably here. It's quite common for the solder holding the pins which plug the speedo into the main circuit board to crack and cause an intermittent speedo, but I'm unsure if any combination of cracks can kill the speedo and leave the odometer working.

[bhaza]

Just wondering if there is a write up on this topic?

[TheMoney]

I had this and I just cleaned up the diff connector with WD40 and it has been fine since. So see if you can get away with that before cutting wires.