Dash fault

I've looked this one up in the manual, no direct reference to your problem, but you can do a self diagnostic check, so it says, by:

with ignition off, hold check button located on right side of instrument cluster, whilst holding it down, turn the ignition on, then release button, it will then do its self test and display a load of code to you.

Might be worth doing to see if it clears your problem

If I may offer a suggestion ref the display:

I've had a similar problem on my Volvo (don't laugh).  I can drive 100+ miles in a day all ok and then if I pop out later in the evening, switching on the headlights will cause all the dials to stop reading and also the analogue clock to stop.  After about 5 mins warm-up time the problem resolves itself and all the gauges re-start working and the clock carries on.

In my case it appears to be a dubious earthing (endemic to many Volvo 7 series) which reveals itself under cold conditions (not vibration related) and has only been there for about a month (owned the car 18mos now)

So I would suggest that the flat battery is not the issue, perhaps there is a dodgy earth for part of the circut to the rear of the dashboard that's causing the problem.  Perhaps being laid up and therefore left colder for a while (over the winter period) exacerbated the problem?

I may be wrong, however, if so, my idea may point others in the right direction.

Good luck.

P.S. Does the display strength of the digital readout change when the car lights are switched on?  If not then it may be getting a voltage feed from the "wrong source", causing it to be permantly lit?

As I said, other people more close to the tech issues of E34's may pour cold water on my idea but ...

Good luck

Ian

What a smashing site, thanks for posting that.What I liked about was how easy it is to select your car.

I've had a BM for a year now, and tend to refer to "E" numbers like the rest of the anoracks, but when I first had mine and needed help it threw me, E what mate, no, mines an F redg 525i etc lol