Speedo stoped working HELP

[woodysjw]

It started jumping about on and off for a while now its
stopped all together but the mileometer still works and so does
my fuel computer thingy 13 button OBC

[stevo]

think theres a sensor on the diff thats prone to braking?

[E30BeemerLad]

the speedo sensor unit is on the diff casing at the rear. The 2 wires that go into the connector plug often get brittle and break. If you are lucky they will have broken some distance from the actual plug, that way you can reconnect using a bullet connector etc. Mine broke right where they go into the plug, so I had to scavenge one off a breaker

here's a pic of my diff, speedo connector/ plug is top right - u can see the broken wire

[dazleeds]

also if its fixable im pretty sure it uses the same plug as the fogs etc hth Daz

[woodysjw]

Thanks will get under and have a look in the morning

[Brianmoooore]

The wire is usually broken inside the plastic sheath, and can only be found by gently stretching the wire.
The cause is probably the copper becoming brittle with vibration, so I would not recommend a repair using the same piece of wire.
Get a similar connector from a scrappy with a foot or so of wire attached, (one of the headlamp connectors is the same, and the yellow plastic bit can be bought seperately from a dealer if its broken), cut the original diff wire well away from the diff and splice your new wire on using soldered joints and heat shrink tubeing.

[mrbless248]

My speedo kept cutting out but the solution was different. The solder on the back of the speedo was cracked, causing it to come on when there was a connection and go off when the connection was broken (by either a bump in the road, heat or cold making the solder swell or shrink).

The best thing to do is follow the instruction on this link (www.unofficialbmw.com/speedo/speedo.html) and that should hopefully solve the problem.

I litterally done it today in about 1 1/2 hrs and now my speedo's fine after some serious testing!!!!

[woodysjw]

Well replaced plug with a big chunk of wire about 10in joined it all in
the old plug just fell to bits thought that this must be the fault.

drove down the road and nothing.??

[Brianmoooore]

Sorry, should read the OP before answering.
If your mileometer is still working normally, then it's nothing to do with the diff cable.
Must be something to do with the speedo itself. Probably something like Mrbless248 says.