The Board Computer on my 91 535i doesn't seem to be "ON". The "BC" switch on the turn signal lever doesn't do anything and there is an empty patch on the instrument panel that should light up with somethin' but doesn't. All of the fuses look OK. I do have the area on the panel that tells me that the "license plate light" is not working, and that's true but I don't care about that. Any ideas out there in BMW expert - land?
Maybe the backlight has died. Is there a very faint reading?
Perhaps you should fix the failure item before attempting to get other less useful information from your computer.
Think of "usefullness" from the perspective of the computer that is trying to inform you of a safety/legal problem. You are asking it to ignore the safety and obvious legal issues and tell you about fuel consumption rates and average speed. You may find this information useful, but the computer may think that burnt out bulbs is a greater hazard to you and those around you.
If the computer is able to report that the bulb is burnt out, then the computer itself functions. Another poster suggested that the back lighing had gone away in the display, and I thought of that one as well. But, if that was the case, then you would not be aware that the plate lights had burnt out.
Fix the plate lights, then see if the display returns to normal.
Okay, good idea. I didn't realize that this was the board computer display. There seems to be some space to the right of this on the instrument panel (lower right corner) that looked like it wasn't "ON", but you're probably right about the computer thinking that the license plate light is priority, because when I push the reset button on the panel itself, all that happens is ... blank...license plate warning goes back on..instead of any other information.
In the interest of full disclosure, your '91 5 Series is different in this respect than my '94 3 Series. If your message display for the busted/burnt out lamps is different than the display of fuel consumption and remaining distance on the fuel load, then your problem is very likely to be the lamps for the back light. On my car, all of this information comes on the same display ...
No, I think you were correct the first time. There must be one display for everything. I checked the fuse (#5) and the bulbs themselves and they seem fine. The bulbs are rated for 12 volts and
65 watts which seems high to me. Why so much power usage for tiny little license plate bulbs? Or maybe this is simply the upper limit for them and not the practical usage level...anyway, I am rather stumped at the moment.
Think you've missed out a decimal point. 65 watts is more than headlamps.
Has it got parking lights operated off the indictor switch? Ie with the ignition and lights off the indicator switch should select one front and one rear light only - for parking on an unlit street. The panel lights and the number plate lights don't come on in this condition so the number plate light has a separate circuit to the other side lights. I'm not sure how they achieve this on your model but some do it via contacts on the indictor switch.
Thanks Dave, I don't know how to turn on the parking lights...I'll find out...I have the automatic headlights so maybe there are no parking lights...I have 3 settings on the instrument panel..the top setting shows a light bulb so maybe that's it...I haven't driven it past my neighbourhood yet because I have it listed as "unfit" and "unplated" while I repair it. I have also prepared a hydroxy booster which I am going to add next week.
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