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1991 BMW 525 computer problems

Tiny
FLYBOY97222
  • MEMBER
  • 1991 BMW 525
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 20,300 MILES
The onboard computer that tells me MPG, Time Date and all the other cool stuff I like to track on my car, has gone dark, I can see the numbers if durring the day but the back light has gone out, but also when I use the dash to pull up the info I only get Time, outside temp, Average MPH, Distance to Empty, and that is all.
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Tuesday, November 18th, 2008 AT 11:03 PM

8 Replies

Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
The OBC is back lighted with 1.5 watt bulbs that can be replaced. Remove the radio and there is a lever in there to release the OBC. It takes a very small screwdriver and small Allen wrench to remove the radio.
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Wednesday, November 19th, 2008 AT 11:17 AM
Tiny
FLYBOY97222
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Thank you very much. But that doesn't answer why I only get partial data on the dash computer now.
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Wednesday, November 19th, 2008 AT 11:31 AM
Tiny
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To restore full operation of the dash display removing the OBC and replacing the bulbs should reset the functionality of the OBC. It is like control/alt/delete on your computer. If that does not work you may need to disconnect the battery for several minutes to achieve the desired results. Keep in touch.
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Wednesday, November 19th, 2008 AT 12:21 PM
Tiny
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Thank you- I will try both. And keep you informed.
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Wednesday, November 19th, 2008 AT 12:22 PM
Tiny
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Let me know if you need a radio code.
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Wednesday, November 19th, 2008 AT 1:56 PM
Tiny
FLYBOY97222
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  • 19 POSTS
Okay- got the OBC out and looks like I need to get the bulbs from BMW? Also I tried unhooking my battery and also just unplugging the OBC but the dash is still giving me partial info. I'm going to try and unhook the battery while I have the computer out.

It never asked for a code? Weird.
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Wednesday, November 19th, 2008 AT 2:07 PM
Tiny
FLYBOY97222
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  • 19 POSTS
I had to order the Bulbs online from Pelican- $.75ea and $7.50 to ship.

I also might think it the other problem might be the OBC control unit. Do you know where that is located?
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Wednesday, November 19th, 2008 AT 3:20 PM
Tiny
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The on board computer is pretty much self contained, there may be something that I just dont remember about the info display, I will try to have a discussion with a contact of mine and see what I can find out ASAP.
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Wednesday, November 19th, 2008 AT 3:49 PM

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