Speedo a bit intermittent...

[miniblob]

Hopefully just a quickie guys...

Last two days my speedo has suddenly decided to work intermittently!!!
Works fine for 90% of the time, then it'll drop to nothing, bounce around a bit, then go back to being fine!!!
It's done this a lot over the last couple of days, so I'm hoping it's something simple!!!

How does the speedo work???
Is there a sensor or cable to the gearbox or something that I need to check - or is it likely to be the dash cluster playing up???

[daimlerman]

Most likely culprit is the plug to the sensor on the diff,the wire goes brittle and cracks,giving the symtoms you describe.

Best fix is to replace as much of the wire as you can get at,seem to remember that the plug is the same as a headlight plug,so a breaker may provide a ready wired plug with a chunk of cable attached.

[miniblob]

I'll have a look if I get a chance - though it sounds simple enough for the guys I know in the local garage to do on tuesday while they're doing a couple of other bits for me!!!

Cheers!!!

[gromgsxr]

mine did the exact same thing, i took the clocks apart heated soldered joints up and added a bit of fresh solder never had an issue since.

[Brianmoooore]

There are two things that go wrong with E30 speedos. One is what Daimlerman says, and the other was gromgswr's problem.
The most common is the broken wire at the diff., but the way to tell is to tap the top of the dashboard hard, and see if this affects the fault.
If it turns out to be the diff. wire, make sure that a length of the cable is replaced complete with plug, not repaired as the average garage monkey will try to do! The physical properties of the copper in the wire will have been changed by vibration from the diff., and a repair will not last.
If it turns out to be the dashboard fault, the culprits are the soldered joints for the pins that plug the speedometer circuit board into the main circuit board.

[miniblob]

Thanks guys - is the complete cable & plug available from BMW, or will it need to be made up??? If its got to be made I'd rather do it myself!!!

[Brianmoooore]

http://2009.bmwfans.info/parts/catalog/ ... ring_sets/ #3 on here is the loom, or you can make it up with bits from here: http://2009.bmwfans.info/parts/catalog/ ... mm_system/ and here: http://2009.bmwfans.info/parts/catalog/ ... g_housing/ but the standard repair is to use a headlamp plug and length of cable from a scrapper.

[capri_rob]

That reminds me - I "repaired" mine with a block connector last year when the cable snapped

[BenHar]

http://2009.bmwfans.info/parts/catalog/ ... ring_sets/ #3 on here is the loom, or you can make it up with bits from here: http://2009.bmwfans.info/parts/catalog/ ... ring_sets/ and here: http://2009.bmwfans.info/parts/catalog/ ... ring_sets/ but the standard repair is to use a headlamp plug and length of cable from a scrapper.

Brian, all three of those links seem to be to the same page?

Ben

[Brianmoooore]

Brian, all three of those links seem to be to the same page?

Ben

Don't know what happened there, but I suspect senility has something to do with it! Hopefully corrected!