speedometer not workin after diff change

[java]

Hi,

I have recently changed my differential and now the speedometer is not working I have checked the plug on the diff and the fuse all is ok. Before changing the diff all was working fine.
Any help would be appreciated,

[Grrrmachine]

There's a chance you've snapped the wires on the plug - they can be very brittle. Try and get some plugs off another BMW in a scrappy, plus 30cm of wire, and solder them to the existing loom.

[johnono]

Almost deffo its the wiring

[TPS]

Almost deffo its the wiring

+1

[Brianmoooore]

Try and get some plugs off another BMW in a scrappy, plus 30cm of wire, and solder them to the existing loom.

Get the identical plug from the headlamp wiring, not wire and plug from a diff., which will be well on the way to suffering from the same problem.

[java]

I have fitted a new plug from main dealer but still speedometer still not working. Also horn has stopped at the same time, any connection between the two?? Would I need to keep my original sensor on diff or does it not matter.

Any help would be appreciated
Thanks

[Brianmoooore]

Plug only, or plug plus wire?
No obvious connection between horn and speedo.

[java]

Yes I changed plug plus wire roughly 30cm

[l16ydl]

Any updates on this? I've got the same issue but not changed the wiring yet.

[l16ydl]

Sorry to hijack the thread, but I am losing my patience on this one. Everything works apart from the speedo. I have put a brand new sensor in the diff, changed 30cm of wiring, checked the wiring at the back of the clocks. Is there anything else that people could recommend?

[Quaser]

maybe the sensor in the diff is naff in the replacement diff

[Brianmoooore]

Disconnect the plug at the diff. and connect an ohm meter across the pins of the sensor. The meter should read short circuit then open circuit several times for each turn of the RH rear wheel.
If all is OK here, disconnect the white plug from the instrument cluster, and repeat the test with the meter connected to pins 8 (brown wire) and 12 (brown/red wire).
Car will start and drive OK with the cluster removed.

[l16ydl]

Thanks Brian, done both of test and the meter is reading a pulse at both ends. Could it be the clocks themselves or is there something else I can try?

[Brianmoooore]

The speedo. module plugs into the main instrument circuit board via pins soldered to the speedo circuit board. The soldered joints for these pins are known to crack, causing speedo issues.
It usually results in an intermittent speedo. rather than totally dead, but worth checking.

[l16ydl]

Sorted, thanks for the help. It ended up being the speedo being burnt out. Put a third set in and it worked. Can they be repaired?