E12 Speedo

[stewart]

Hi Guys Need some advice on my speedo, sometimes it works and sometimes it just stops showing my speed then next time i start the car it works again, when the speedo stops the fuel economy meter bounces back and forth
anyone have any idea's as to what it could be
thanks

 

[Psymon69]

for speedo check the diff plug. those get brittle and dont make contact, that causes needle to jump around. otherwise the SI board might be going...

 

[stewart]

that sounds expensive .....

 

[Adi]

Have you checked the batteries inside the cluster? There are two behind the fuel and temperature gauges

 

[stewart69uk]

Adi I will check in the morning are they a standard battery ?
might be worth changing them anyway, the fuel, temp, rev counter all seem to work fine

 

[Adi]

they are re-chargeables ones, with a special mounting / bracket. Sometimes they leak and cause havoc on the PC board

 

[Cat]

for speedo check the diff plug. those get brittle and dont make contact, that causes needle to jump around. otherwise the SI board might be going...

its a e12 not a e30

 

[Psymon69]

for speedo check the diff plug. those get brittle and dont make contact, that causes needle to jump around. otherwise the SI board might be going...

its a e12 not a e30

surely they work on the same principals seeing as they are from the same era...

 

[symmat001]

Is it an e12/8? Or normal e12

If e12/8, My e28 does the same thing, and batteries were leaking, had new ones put in, but turns out the leak ruined my PC Board. need a new one

 

[stewart]

Its a 1985 E12/8 I believe

 

[Adi]

Have a spare pwc board, in case somebody is interested. Pm me

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For a e12/8

 

[stewart69uk]

O.k Took out the speedo and this is the back

where's the batteries ? don't wanna start taking it apart if its gonna fall apart had a bad experience with a merc speedo many years ago

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Whats the yellow plug for ? I don't have a cable plugged into the back of it

 

[Adi]

they are inside, and not that easy to get to. Undo all screws, lift front part off carefully.

Take out Speedo and Ref counter, they clip out, careful with ref counter, has a part that stickes and gets caught.

Then in the middle section behind the petrol and temperature gauge is where the batteries sit, you need to undo tow screws. VERY VERY careful with the ribbons that go between the parts they might be brittle and break.

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in this link you see the bits and pieces:

http://www.bmwe34.net/E28/Repairs/Dashboard.htm