no speedo?!!!!!

[richo]

hi hope someone can help me? i was driveing my 1989 325i last nite when the speedo started playing around jumping around and then just packed up! havnt looked into this yet just woundering if anyone else has come across this and what it mite be? is this cable driven or electrical? if its cable guessing shouldnt be to hard to sovle, how ever if its electrical where do i start? can anyone tell me where the sensor is located on the engine for it?
please help ive no idea how fast im going!!!!!!
thanks richo

[Gwynleym10]

hi hope someone can help me? i was driveing my 1989 325i last nite when the speedo started playing around jumping around and then just packed up! havnt looked into this yet just woundering if anyone else has come across this and what it mite be? is this cable driven or electrical? if its cable guessing shouldnt be to hard to sovle, how ever if its electrical where do i start? can anyone tell me where the sensor is located on the engine for it?
please help ive no idea how fast im going!!!!!!
thanks richo

Sensor is located in the back of the differential. If you look from the rear of the car at the diff its the only electrical wire going into it.

Also look at the fuse... but if it failed slowly then its probably not that.

Other than the sensor (take it out and clean it) and the wire it can only be the guage.

[richo]

cheers mate ill have a look at that
many thanks

[Geeman]

You can get a replacement plug for the diff fom the dealers... only a few pence. Splice it into the existing wiring, and hey presto - working speedo!

Giles.

[Widge]

Have you ever done that Geeman? Cos whe n I wwent to the dealers it wan't that simple, they are moulded on to the end of the cable when the loom is made. The plastic surround then clips round the wires.

[Geeman]

Yeah... just use the wires coming out of the new plug and splice them into the existing wires... heat shield it and job's done.

[Finny]

yeh its easy i did one on my mates car turned out that the sensor was ok just the wiring was a bid dogey the wires had corroded so just cut off the crap bits and spliced it back together.

[Brianmoooore]

This is a very common fault. The wire(s) to the diff will have fractured internally near the plug that goes to the diff.
I think the copper wire is "work hardened" by vibration from the diff, and becomes brittle.
For this reason the break shouldn't be repaired, but a 300mm - 400mm length of wire minimum should be replaced complete with plug.
An identical plug with wire attached can be cut from one of the headlamp connectors on a scrap E30.

[damian]

My Brother-in-law encountered the same problem last Summer. The speedometer is electrical, and is attached to the instrument cluster panel as one unit in the dash. We tried different clusters from the junk yards, and at one point we thought the batteries in the instrument panel were fried. I think the problem was solved, however, when we changed his actual cluster's housing that holds the "service" circuit board. We did not have to deal with the differential at all. A few hints; make sure the cluster is for your model and not for the 4 cylinder or 325e models, as the 4 might give a false reading, and the 325e only revs to 5000 rpm on the odometer. Notice I said the (whole) cluster to change, we tried swapping the guages alone and ended up frying the circuit board. Also the boards are very susceptible to static electricity so discharge all static before proceeding. I know this was quite a mouthful but I didn't want you to make the same mistakes that we made! Good Luck!

[richo]

blimey i hope i dont have to go through all that? Fingers crossed ill be ok as i got under the back today and found the senor and unpluged it and cleaned it up and stuck it back in again. i then took it for a drive and the speedo worked for about a mile so hopefully the problem is there? im gona ave a trip down the scrappies and get me a headlamp plug and wire like you suggested brianmoooore. Fingers crossed that will do the trick????