Weird Electrics Solved

[Steeler]

Odd thing happened tonight. 2 things happened simultaneously.
Signal bulbs operate but there is no sound in the cabin or lights lit to indicate signals are working. Also radio volume increased dramatically on its own(not from vehicle speed increasing) and then went dead. HU still lights up but no sound.
Could both these occurrences be coincidence?
Any ideas??

[dc_wright]

When mine had similar issue it was the steering angle sensor that was the issue. It had locked up and frozen the i-bus so any communications on it were corrupted. It affected all the controls on the steering wheel and since I have the multi-function steering wheel it affected the radio controls also.
When mine happened it was the afternoon before I was set to leave on an extended road trip so I didn't have time to try anything on my own. The dealer shop reprogrammed the sensor ($200) and it's been fine since. That was 3 years ago.
Given what I know now, first thing I'd try is disconnecting the positive battery cable for 20 minutes to ensure everything is shut down, then reconnect and see if the problem is gone. When you do this it forces all of the sensors to do a "cold boot" and do a fresh load of any on board software. The reset might fix the bus hang and you'll be good to go.

[Steeler]

Thanks DCW,
I will give that a try

[Steeler]

OK so having dealt with Lucas wiring my whole "weekend vehicle" life, electrical gremlins are not new to me.......but here is what is going on now.

Disconnected and reconnected the battery with no change to the 2 symptoms in the OP.
However another issue has arisen. The chime that goes off with door open and key in ignition is going off with key out of ignition and door closed and locked.
I have disconnected the battery again. Will report back.

Edit. Reconnected battery and all is back to normal.
Could this be a grounding issue somewhere?

[wdb]

Is your battery good? These cars have a rep for wonky stuff happening when the battery is weak.

[Steeler]

Yes battery is good.

Happened again at a drive through window.....radio turned itself up full blast. I shut the car off, restarted it and it did not happen again in the 2+ hours of driving home.
Hopefully this isn't a precursor to electrical issues.

[inTgr8r]

Wish I could help Dave, this sounds a little unusual for the common weak battery issue.

On coupe #2 here, there was an issue with radio volume that was erratic + various dash lights.
Turned out that battery + terminal was not fully tightened.

Cleaned it up and added some dielectric and so far no more problem.

[Steeler]

Originally Posted by inTgr8r

Wish I could help Dave, this sounds a little unusual for the common weak battery issue.

On coupe #2 here, there was an issue with radio volume that was erratic + various dash lights.
Turned out that battery + terminal was not fully tightened.

Cleaned it up and added some dielectric and so far no more problem.

Thanks Ian, will check connections in trunk and under hood.

[Steeler]

OK so everything connected securely underhoid at the battery.

Still have same 2 issues. Noticed tonight that the clock on the radio does not move yet the clock on the dash display is keeping perfect time.

Could there be a plug behind the steering wheel airbag not fully connected?
Will investigate tomorrow

[wdb]

That sounds like it could have something to do with the <whatever> bus in these cars. Is there a 'reboot' procedure I wonder.

[Steeler]

OK so in the interest of closure and helping others in the future.
Please read and follow this article https://www.bmwgm5.com/ "KBus Troubleshooting"

Our X10116 is on the right side of the passenger footwell up and behind the dash.
There is a clip on the back of the block that you push in while pushing the block upwards to release it so you can get to the ground bars.

The culprit for me was the 3rd lug. All electrics came back online for me after this ground was removed.

The only error code now is anti trap for the windows because of its ground being removed. This actually makes sense now as the initial electrical issue was non operable passenger window switch.

Moral to this story is always repair inoperable electrical components before they cause additional issues.

[RossBMWZseries]

Great news Dave! I’m glad you were able to figure this out and thanks for giving us a heads up on this. I’m a bit confused though;

The 3rd lug was plugged in and you unplugged it, causing the anti trap error code but also solving all your issues?

[Steeler]

Yea I know.
Electrics is not my strong suit either.
As far as I understand, the ground for all of the body electric systems share this same ground. If one of those systems has an issue then it can affect the others. So isolating the “bad system” by unplugging it’s ground brings all other systems back online.

If I am off base on this please someone step in.

Now to find the issue with the power window wiring. BTW both windows are operable from the drivers switch so my issue is isolated to the passenger switch.

[StickMon]

Unplugging fuses to remove power would be the preferred way of isolation.
Unplugging a ground with power applied is usually a bad idea, since the current may find it's way to ground through another path, sometimes with crazy results.
Like you turn the radio on and the wipers start going.
But what works, works.

[wdb]

Originally Posted by StickMon

Like you turn the radio on and the wipers start going.

Sounds like my old '68 Camaro. Turn on a turn signal, then hit the brakes; interior lights go out. Chevy was being, uhm, 'inventive' with ways to save on wiring in those days.

[StickMon]

Yep. Vehicles that used the chassis as return were notorious for that.
I had a Suburban that when you put on the left turn signal it flashed the backup lights.
All the grounds on each tail light assembly were crimped onto one lug screwed into the chassis.
Left side rusted loose so the return current from the left side lights flowed through both backup lights to the good ground on the right side.

[Steeler]

Originally Posted by StickMon

Unplugging fuses to remove power would be the preferred way of isolation.
Unplugging a ground with power applied is usually a bad idea, since the current may find it's way to ground through another path, sometimes with crazy results.
Like you turn the radio on and the wipers start going.
But what works, works.

Noted stickmon
So even easier than getting that damn block out and working in a cramped area would be to pull a fuse at a time until the the signals or whatever is malfunctioning come back on.

Regardless I found the culprit chafed wire in the power window switch circuit.

[RossBMWZseries]

Does anyone know if the Z4M and Z4 have the connection block in the same location (under passenger footwell attached to the firewall)? The non M Z4 does based on pictures Dave provided. I can’t seem to find the connection block in my car though

[Steeler]

Originally Posted by RossBMWZseries

Does anyone know if the Z4M and Z4 have the connection block in the same location (under passenger footwell attached to the firewall)? The non M Z4 does based on pictures Dave provided. I can’t seem to find the connection block in my car though

Ross, the M's have a connector indicated in the TIS the same as the Non M's.
Hope this helps.


Edit. My apologies, that is incorrect the X10016 in the non M does not show up in the M.
Maybe there is a different "X" to the same part in the M.

Edit#2 So I had the connector # incorrect. Both M and non M use the same comb connector X10116. From the TIS it looks like the connector is in the same location.

https://www.newtis.info/tisv2/a/en/e...dapter/m8xdSOk

https://www.newtis.info/tisv2/a/en/e...apter/FE20HkDV

[RossBMWZseries]

Yea you’re right Dave, looks like both M and non M are in the same location.

Does anyone know where the hell my connection block is? I don’t see it anywhere

[RossBMWZseries]

Originally Posted by StickMon

Unplugging fuses to remove power would be the preferred way of isolation.
Unplugging a ground with power applied is usually a bad idea, since the current may find it's way to ground through another path, sometimes with crazy results.
Like you turn the radio on and the wipers start going.
But what works, works.

StickMon, are you saying that I could troubleshoot the Kbus by removing fuses instead of unplugging the modules’ ground connections? If so, there’s about 12 modules in the K bus, anyone know which fuses pertain to which module?

[StickMon]

I don't think the wires dbarton62 has in post #11 above are grounds.
Those appear to be the K-bus connections.
I think you found yours in post #16 in the other thread, but they're not spliced the same.
Are you the original owner? Looks like somebody had some previous trouble and got rid of the quick disconnects in favor of hard splicing everything.