Is it the SI board?

E28 technical advice asked and given! Troubleshooting, modifications and more.
Mike W.
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Re: Is it the SI board?

Post by Mike W. »

OK, I did not go thru the ETM. But E12s sometimes had a problem with one or both turn signal indicators not working which turned out to be the hazard switch. A much more clunky design than the E28 ones, but there was a lot of stuff going thru them. And apparently sometimes one contact would sometimes not make. I wouldn't be surprised if the same existed in rare cases on E28s. Again on E12s, all signs pointed to the flasher relay. I even went to the point of swapping transistors inside one, to no avail. But no, it was the hazard switch.
Mashford
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Joined: Jun 19, 2006 2:15 PM
Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

Mike W. wrote: Dec 08, 2022 11:37 PM OK, I did not go thru the ETM. But E12s sometimes had a problem with one or both turn signal indicators not working which turned out to be the hazard switch. A much more clunky design than the E28 ones, but there was a lot of stuff going thru them. And apparently sometimes one contact would sometimes not make. I wouldn't be surprised if the same existed in rare cases on E28s. Again on E12s, all signs pointed to the flasher relay. I even went to the point of swapping transistors inside one, to no avail. But no, it was the hazard switch.
Hey Mike W! Thank you (for what, the 25th time?)! So you recommend replacing hazard switch? Not sure if you meant the switch or a relay on e28. For that matter, I don’t know if there is a relay on this e28. But I am looking at the switch now. Thanks again.
Mashford
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Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

Mike W. wrote: Dec 08, 2022 11:37 PM OK, I did not go thru the ETM. But E12s sometimes had a problem with one or both turn signal indicators not working which turned out to be the hazard switch. A much more clunky design than the E28 ones, but there was a lot of stuff going thru them. And apparently sometimes one contact would sometimes not make. I wouldn't be surprised if the same existed in rare cases on E28s. Again on E12s, all signs pointed to the flasher relay. I even went to the point of swapping transistors inside one, to no avail. But no, it was the hazard switch.
Thanks again Mike W, for what, the 25th time? So you suggest replace switch (not relay)?
Mashford
Posts: 518
Joined: Jun 19, 2006 2:15 PM
Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

Mike W. wrote: Dec 08, 2022 11:37 PM OK, I did not go thru the ETM. But E12s sometimes had a problem with one or both turn signal indicators not working which turned out to be the hazard switch. A much more clunky design than the E28 ones, but there was a lot of stuff going thru them. And apparently sometimes one contact would sometimes not make. I wouldn't be surprised if the same existed in rare cases on E28s. Again on E12s, all signs pointed to the flasher relay. I even went to the point of swapping transistors inside one, to no avail. But no, it was the hazard switch.
Thanks again Mike W, for what, the 25th time? So you suggest replace switch (not relay)?
Mashford
Posts: 518
Joined: Jun 19, 2006 2:15 PM
Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

Mike W. wrote: Dec 08, 2022 11:37 PM OK, I did not go thru the ETM. But E12s sometimes had a problem with one or both turn signal indicators not working which turned out to be the hazard switch. A much more clunky design than the E28 ones, but there was a lot of stuff going thru them. And apparently sometimes one contact would sometimes not make. I wouldn't be surprised if the same existed in rare cases on E28s. Again on E12s, all signs pointed to the flasher relay. I even went to the point of swapping transistors inside one, to no avail. But no, it was the hazard switch.
Thanks again Mike W, for what, the 25th time? So you suggest replace switch (not relay)?
chilone
Posts: 47
Joined: Jun 27, 2022 9:59 AM
Location: Colorado

Re: Is it the SI board?

Post by chilone »

Blue Shadow wrote: Dec 07, 2022 5:08 PM
It seems odd that the high beam indicator is working, just not the low beam?

There is no low beam indicator in the dash. The other lamp on US cars is the fog light indicator. On € cars the third one is for rear fog lights.


Any idea about the "check" light?
The Check light flashing in the middle of the gauge cluster is an indication of the need to Check the overhead indicator console above the rearview mirror. The car monitors brake lights, rear lights, license plate lights, low beam headlight, oil level, coolant level and washer fluid level. The Check light comes on and flashes when you start the car and if all the associated checks are good it will extinguish when you press the brakes the first time (verifying the brake lights work). If it continues to flash the Check panel will indicate the error. The check light can be extinguished by pushing the check panel button to acknowledge the indicated errors found.
Will do. I would have never thought about that! Thank you.
Mashford
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Re: Is it the SI board?

Post by Mashford »

I have no idea why my response to Mike W. went out multiple times. Well, it could be because I was fat-thumbing my phone. Sorry.
Blue Shadow
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Location: SE PA

Re: Is it the SI board?

Post by Blue Shadow »

Mashford wrote: Dec 09, 2022 11:32 AM I have no idea why my response to Mike W. went out multiple times. Well, it could be because I was fat-thumbing my phone. Sorry.
Hey, your thread you can fill it up if you want. You could go in and edit the second post with some new nugget of info and no one will know.

As to the 'Check' light, I was replying to chilone who added that issue to his comments about the SII board. Usually recommend new threads for new issues but his was similar with a different issue added. All cleared up, I hope and we can get back to the specific issues you are having.
Mike W.
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Location: California Whine Country

Re: Is it the SI board?

Post by Mike W. »

Mashford wrote: Dec 08, 2022 11:53 PM
Mike W. wrote: Dec 08, 2022 11:37 PM OK, I did not go thru the ETM. But E12s sometimes had a problem with one or both turn signal indicators not working which turned out to be the hazard switch. A much more clunky design than the E28 ones, but there was a lot of stuff going thru them. And apparently sometimes one contact would sometimes not make. I wouldn't be surprised if the same existed in rare cases on E28s. Again on E12s, all signs pointed to the flasher relay. I even went to the point of swapping transistors inside one, to no avail. But no, it was the hazard switch.
Hey Mike W! Thank you (for what, the 25th time?)! So you recommend replacing hazard switch? Not sure if you meant the switch or a relay on e28. For that matter, I don’t know if there is a relay on this e28. But I am looking at the switch now. Thanks again.
My comment is a maybe, not a statement.

In the old days when one would typically be available at the local junkyard for a five spot, I would have said yes. Given likely cost and availability now I'd spend some time with a meter trying to figure out if it's working as it should.
Mashford
Posts: 518
Joined: Jun 19, 2006 2:15 PM
Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

Mike W. wrote: Dec 08, 2022 11:37 PMBut no, it was the hazard switch.
Hey Mike W -- I got a new relay from Pelican Parts and have an OEM hazard switch on back order from Germany. :roll: I am still dealing with only one working turn signal indicator (the right).

Meanwhile, before putting everything back together, I...
  • soldered in new batteries and replaced a bunch of the cluster lights
  • replaced the OBC backlight (note: some bulbs are freely pulled in and out and are generic (available from auto parts store), and some are in fixtures and are BMW special order only
  • used heat-shrink butt connectors to install a replacement head light connector unit
I was noodling on ways to make the replacement head light connector (bought used on the forum) to last longer than the last one. This is the second one that has just crumbled in my hand when I was disconnecting from the headlight switch unit. I decided to use spray on rubber coating, the kind you can also get in cans to "dip" tools in to make them "grippy". I protected the connectors with tape and put on about 4 layers. It created a sort of rubber case around the connect. Fingers crossed on that one.

The tach and temp gauge are working now, as a result of new batteries! :banana:

But somewhere upon reassembly I lost the speedometer and fuel gauge. :? I will check fuses and search the forum for clues on that negative outcome. I welcome any ideas and hope I don't I have to pull the cluster and circuit board again. That is a bit of a PITA.

This all took a bit longer because I pulled the seats for easy access to the dash and to clean the carpet and work on some seat covers. I was also doing this on the fly evenings and weekends and over the holidays.

I am really happy to have the tach and temp back, but a bit bummed the speedo and fuel gauge went out along the way -- hopefully an easier fix.

Happy to answer any questions in more detail to help anyone with similar issues. Soldering is not hard. Batteries are readily available from Amazon, etc.
Mashford
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Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

Just did some further forum searching and test driving and see that the speedometer, primary odometer, and trip odometer are not working, nor is the AVG MPG read out changing on the OBC during driving (about 5 miles). And, as above, the fuel gauge is not registering.

I don't think I need to check C103 connection to ECU, as per some posts, since the tach and real-time MPG are working fine (with new batteries).

I am beginning to fear it may be the circuit board. :(
Mashford
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Location: Takoma Park, MD

Re: Is it the SI board?

Post by Mashford »

I just read this in an old post citing loss of speedometer:

"Well, seems the problem was right in front of me all along. Apparently 3 of the wires related to powering the speedometer (white 26-pin connector) and sending the signal from the rear differential, were somehow incorrectly positioned, causing no reaction from the speedometer."

I will pull the instrument cluster and check the connector tomorrow to see if that is source (don't know why that would cause the OBC average MPG read out to not respond).

I welcome any advice at this juncture.
Galahad
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Re: Is it the SI board?

Post by Galahad »

OBC gets it's speed (and from that calculates miles / mpg) from the instrument cluster
Mashford
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Re: Is it the SI board?

Post by Mashford »

Galahad wrote: Jan 08, 2023 12:21 AM OBC gets it's speed (and from that calculates miles / mpg) from the instrument cluster
OK. Thanks. Didn't get to it today...
Mashford
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Re: Is it the SI board?

Post by Mashford »

Does anyone know what this <<(white 26-pin connector)>> refers too in the quote below?

"Well, seems the problem was right in front of me all along. Apparently 3 of the wires related to powering the speedometer (white 26-pin connector) and sending the signal from the rear differential, were somehow incorrectly positioned, causing no reaction from the speedometer."

I copied this from an old post on diagnosing a dead speedometer, and can't find that post any more. I am still searching.

I thought it was referring to the back of the instrument cluster, but those main connectors are blue and yellow.

Thanks.
Mashford
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Re: Is it the SI board?

Post by Mashford »

I found the topic from 2018 with that quote:

viewtopic.php?f=3&t=146860

Meanwhile, pulling the cluster and checking my re-assembly work from before.
Mashford
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Re: Is it the SI board?

Post by Mashford »

:roll:

Of course, it is connected to the instrument cluster. It had fallen down behind the dashboard fascia so I didn't see it to reconnect; I forgot about it.

:oops:

All back together now and fuel gauge is working, so I suspect the speedo will be fine, too, when I drive tomorrow.

Thanks. Should be able to "close" this out now.
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