Multiple System Failures

[rchl19691]

Hello everyone,
I ran into a problem on my 2015 328ix (91k trouble free miles)the other day and it went away then came back this morning. My apologies for the long post.

I was driving on interstate about 70mph and it wasn't raining at the time. All at once my radio goes out (was connected to BT on iphone), sunroof won't open, heater/AC out, center console out, turn signals blinking much faster than normal, CEL on, Driver restraint system warning light on, Lighting system failure light on. When I arrived home I shut her down and a few minutes later a neighbor said my tail lights were on. I go to check & sure enough they're lit up along with the interior heating/cooling system console lights. I couldn't get them to go out so I disconnected the (-) terminal from battery in trunk. This was an endeavor because on top of those issues now the trunk lid won't open so I had to climb in from back seat and pull the internal trunk release. Everything off now.
I let it sit at least 10 hours like that then reconnected battery & same results except tail lights weren't stuck on, yet now fuel gauge is showing out even though I had 3/4 tank. I took it to local dealer who confirmed the symptoms upon drop off but when they actually went to check it out everything was fine. I paid the diagnostic fee then drove home and it was fine all day.
The next morning I'm taking my kids to school and out of nowhere it started again, exactly as the first time with all systems failing.

I live in Ohio and it has rained every day for a week. I've looked for loose wire harnesses & pushed in all the fuses that I could find in trunk. No luck. No leaks and nothing wet that I can see from in trunk. It is raining again so I can't look under car.

The dealer offered to inspect the CANBUS (his word) at the cost of a few more hours and no guarantee on the outcome.

Does anyone have any suggestions or experienced this before? I love this car & would buy another but I have a negative equity situation and 2 more years of payments. (Nothing down, 0% financing) The dealer has done all maint and service so I'm at a loss.

[328 Power 04]

It's probably a short somewhere taking down a canbus system or the flexray system (a different type of internal network).
The error readout should have had historical codes that would have greatly helped us understand the problem, even if it wasn't present at the time. See if you can get that.
It's probably a simple short, or a module taking everything down. It would just take some digging into finding it. These cars aren't as bad to diag and investigate as people make them seem.

[khammack]

Another possible cause of multiple random issues, such as yours, is a battery going bad, but I would be surprised the dealer didn't check it. It would be worth while to ask them if they did.

[White94RX]

If the battery was going bad, there would be under voltage faults stored in the control modules. In that case, even a rookie tech would try and sell you a battery. I doubt that's the issue. More than likely there is one faulty module, and it's stopping all communication on the bus network. It could be a short in the wiring, but that's rare (excluding rodent damage, that's always possible).

[marvinstockman]

Make an adapter so you can put power in thru the cig lighter.