88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Specific conversations and info for the BMW E28 M5 and M535i.
Post Reply
Curtispsf
Posts: 70
Joined: Aug 19, 2013 10:26 PM

88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Post by Curtispsf »

Hi,

I noticed a draining battery and one "history" bar that was red and one that was green that both remained on when the car was off. A mechanic diagnosed a bad instrument cluster, so I had the instrument cluster refurbished and was told that the batteries were replaced. When I got it back all was good. The permanently red and green history bars were gone. I "SEEM" to remember? that when I got it back I had several lit green bars, but now the only time I see green lit bars is when I put the key in and am starting the car up. Once running, I no longer see any lit green history bars.

Are the green history lights supposed to be on when running after an instrument cluster refurbishment with replaced batteries? The reason I ask this question is that the battery drains dead after 2 days of no running. I brought the battery back from the dead with a charger, but I wonder about the battery which is only 1.5 years old holding the charge.

All the cluster instruments are fully functional ( they were on/off intermittently before the refurbishment) but no green history lights. I understand that some refurbs of the instrument cluster bypass the batteries with the result that there are no history lights anymore, but mine supposedly had replaced batteries. If that is the case, shouldn't I see some lit green history tabs?
Preyupy
Posts: 327
Joined: Jun 21, 2012 12:48 AM
Location: Issaquah WA

Re: 88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Post by Preyupy »

The green and orange Service Interval Indicator lights will come on when you first turn on the key. When they have been reset they should all come on and as you get closer to the service they will go out one by one. Where there are no green lights you will get Oil Service lit up and this stays on even once the engine is running. When all of the orange lights go out you will get Inspection showing. To turn these off you need a reset tool (there is a secret handshake that you can do if you don't have the proper tool I just can't remember it off the top of my head).

I seriously doubt that the SI board is causing your car's battery to go dead after 2 days. You have a draw somewhere in the car. Check your glove box light, dome lights, radio (memory), Additional amplifyers, central locking, aftermarket alarms and remote access systems, clock/trip computer. These are all things that are active when the key is off.
Curtispsf
Posts: 70
Joined: Aug 19, 2013 10:26 PM

Re: 88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Post by Curtispsf »

Hi Preyupy,

Thanks for your quick response. Can you clarify one thing for me? The fact that the REFURBISHED instrument cluster showed green lights at first and no longer does is it at all possible that the instrument cluster might be causing a parasitic draw?

I'm also going to look at the interior light switch. I recently reset it to come on when the doors are opened but it does nothing when I turn the setting to permanently ON...no lights. Today, I'm going to turn it to "OFF" based on a previous thread where that was causing a draw. What do you think?

Thanks,
Curtis
Preyupy
Posts: 327
Joined: Jun 21, 2012 12:48 AM
Location: Issaquah WA

Re: 88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Post by Preyupy »

If the battery has gone dead it can cause the SI board to default to no green lights but it is also common for the SI biard to fail and not hold its memory ( there is a battery soldered to the board that may have failed). We replaced a lot of these boards under Warranty and even more by the mid ‘90s they were always a major PITA. A lot of people have just disconnected them after replacing 3-4 of them.

Get a tester and start pulling fuses and jump them to check the current load with everything turned off this will give you a place to start on the search for your current draw. I once had the micro switch in the driver’s door that triggers the “dead bolt” locks that would stick and keep the power lock system active but not actually lock the doors ( only took 4-5 hours of warranty diagnostic time).
Curtispsf
Posts: 70
Joined: Aug 19, 2013 10:26 PM

Re: 88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Post by Curtispsf »

Thanks again for your response. Lots to consider. I also figured out that the green lights are only supposed to light when the key is clicked on. And they do. All green. I mistakenly thought that the green status lights remained on when running. That was based on some [now known to be faulty] memory. :laugh:
Preyupy
Posts: 327
Joined: Jun 21, 2012 12:48 AM
Location: Issaquah WA

Re: 88 M5 INSTRUMENT CLUSTER REFURB. ELECTRICAL ISSUE

Post by Preyupy »

The green, yellow and orange lights only come on for a few seconds when you turn the key on. the Oil change and Service lights stay one once they have been triggered.
Post Reply