The batteries used in older BMW instrument clusters were on the service indicator boards and I dont think they would eb your problem.
You have a busted gear I think.
Read this
http://www.z3bimmer.com/OffTopic/E24Bimmer//OdoGear/
Originally Posted by
mustard
Right, I've done the 'test' everything lights up perfectly (unlike our 518 which the one digit on the trip is permantly out) the display seems to come into life (and stays lit) when the car is used for regulary, if it is left for a day or two it rather it disappears and returns when the car has done a decent journey.
Is there a battery of some sort on the circuit board? Is it not holding charge properly? Would replacing this battery (if there is one) solve the problem or am I best off getting a new (probably 2nd hand board)?
Cheers
Current
2008 M5 6 Spd
2000 Z3 2.8 5 Spd MSport
2012 X5 35d Sport
1995 540i 6 Spd
1992 535i 5 Spd
Former
1995 530iA
1986 635CSI 5 Spd
2011 X3 2.8 MSport