E30 battery behind the dash problem...

[seaside_sophie]

Hi,

Can anyone help at all... I need to know what the battery behind the dash does in my BMW E30. I have been told that it is the MPG indicator!? Is this right.. if so is it just that.

Also how much work is involved in replacing it?

Cheers,

Sophie

[m3evo2]

The batteries are for the service indicatior, the green lights etc. They are soldered to the board and can be replaced, or new SI board. Other signs can be intermittent wobbles of the dash needles. No big worries to sort, specialist your best bet, main dealer expensive.

Edited by m3evo2 on Tuesday 9th January 20:02

[Fixedwheelnut]

You have to take out the instrument cluster and strip it down to remove the SI board that houses the two AA batteries.
you can replace them on the board with a soldering iron or get a two AA battery holder from Maplins and some twincore wire and solder this in and mount the battery holder under the dash with a couple of rechargeable batteries in.
It makes them much easier to replace in the future, thats what I did withmine

[rlk500]

Alternatively, you may find that you cannot resolder new batteries onto the board. There are a couple of types of board depending on age and model of E30. I had to replace my complete SI board, which was about £90 exchange. Other signs that it may be the board are non working Tacho and/or an inability to re-set service lights.

[Cotty]

Or you could just turn them off, I have.