[18lstroup]

In My 2008 335xi coupe all my lights flicker. Interior and exterior. Battery and alternator are good ... Where are the ground locations? I found the one by the battery and the two on the strut towers where are the others?

[ewicky]

there's like a dozen or more. check out newtis.

might be an FRM module. personally I'd check your system with a voltmeter to see if the supply voltage is actually fluctuating.

[gbalthrop]

Originally Posted by 18lstroup

In My 2008 335xi coupe all my lights flicker. Interior and exterior. Battery and alternator are good ... Where are the ground locations? I found the one by the battery and the two on the strut towers where are the others?

As ewicky suggests, if ALL lights flicker, interior & exterior, when the vehicle is stationary with motor running, but NOT when engine is OFF, then you probably have an issue with alternator voltage output, either due to a Voltage Regulator fault, or a loose connection in the Alternator/Battery circuit.

First diagnostic step I would suggest (after testing engine on/off as described above) is to activate "Hidden Menu 9.00" as described in link below to display system voltage on your instrument cluster, and watch for voltage fluctuation as motor runs. Of course you can also read System Voltage parameter on a scan tool connected to the OBD II socket, or connect a voltmeter to the lighter socket. An old analog voltmeter might show rapid fluctuation better than a digital device:
http://e90.wikifoundry.com/page/BC+hidden+menus

Vary RPM while stationary in Park, and see what happens. Check ALL 12V+ Battery Connections and Chassis ground Negative Battery Terminal per this TIS circuit diagram for your Voltage Supply System:
https://www.newtis.info/tisv2/a/en/e...or-ibs/aeTiAe0

Please let us know what you find,
George

[18lstroup]

Will check voltage And such tonight again. I called the local BMW tech and he said he thinks it's probably the FRM module. I will check all of those first

[18lstroup]

Just accesed the hidden volt meter. With just the ignition on the car was at 12.1 volts after starting the car it went up to 15. Fluctuate between 14.8 to 15 volts. Strange enough the lights flickered the hole time I was sitting there then I went for a drive and they started to work 100% normal. Came home sat there in neutral and they never flickered again. So at this point I'm assuming it's a bad wire connection.

[ewicky]

Originally Posted by 18lstroup

Just accesed the hidden volt meter. With just the ignition on the car was at 12.1 volts after starting the car it went up to 15. Fluctuate between 14.8 to 15 volts. Strange enough the lights flickered the hole time I was sitting there then I went for a drive and they started to work 100% normal. Came home sat there in neutral and they never flickered again. So at this point I'm assuming it's a bad wire connection.

Your battery won't last long at 15V. Something is wrong, and not just with flickering lights.

[18lstroup]

Originally Posted by ewicky

Your battery won't last long at 15V. Something is wrong, and not just with flickering lights.

As in my charging system? What would make it over charge?

[gbalthrop]

Originally Posted by 18lstroup

...I called the local BMW tech and he said he thinks it's probably the FRM module...[don't think the FRM is the cause of lights flickering in your case -- that's most likely change in system voltage -- the alternator charging system that supplies power TO the FRM -- see comments in the Blower failure thread]

Originally Posted by 18lstroup

Just accesed the hidden volt meter. With just the ignition on the car was at 12.1 volts after starting the car it went up to 15. Fluctuate between 14.8 to 15 volts. Strange enough the lights flickered the hole time I was sitting there then I went for a drive and they started to work 100% normal. Came home sat there in neutral and they never flickered again. So at this point I'm assuming it's a bad wire connection.

Originally Posted by ewicky

Your battery won't last long at 15V. Something is wrong, and not just with flickering lights.

Originally Posted by 18lstroup

As in my charging system? What would make it over charge?

It is NORMAL (at least on my car ;-) for system voltage to be 14.8 to 15.0V with the motor running, at idle, after startup. I don't know what the algorithm for setting "Overvoltage" fault code in the DME is per the BMW FC & P-code listed below, but it appears to be MORE than 15.0V, as I have seen that number often, and NEVER had EITHER an overvoltage code or "light show" on my instrument cluster, where multiple warning icons suddenly flash, such as DSC, TPMS, ABS, etc.

Of course the battery voltage BEFORE starting the engine is somewhere in the 12.0 to 12.7V range, and immediately goes up to 14.5 to 15.0 after engine start, as the alternator is charging as much as it can to replenish Starter draw.

It seems to be MORE than a coincidence that your blower motor quit working at (about) the same time as your lights quit flickering. I would get the Blower Harness recall performed. Actually I would inspect the wiring harness BEFORE getting the recall performed as that circuit is BATTERY POWER (UNswitched) as far as the power supply via F88 to the Blower Final Stage Connector. I would PULL F88, inspect it to see if it blew, and NOT reinstall it prior to blower harness recall perfomance. See wiring to N2, Blower Output Stage, in this TIS schematic:
https://www.newtis.info/tisv2/a/en/e...bution/ufClUrJ

My SWAG is that with that fuse pulled, you will have NO more flickering lights. For SURE, you will have no concern of electrical fire due to blower harness failure prior to recall -- IF you have pulled F88.

George

[18lstroup]

Originally Posted by gbalthrop

It is NORMAL (at least on my car ;-) for system voltage to be 14.8 to 15.0V with the motor running, at idle, after startup. I don't know what the algorithm for setting "Overvoltage" fault code in the DME is per the BMW FC & P-code listed below, but it appears to be MORE than 15.0V, as I have seen that number often, and NEVER had EITHER an overvoltage code or "light show" on my instrument cluster, where multiple warning icons suddenly flash, such as DSC, TPMS, ABS, etc.

Of course the battery voltage BEFORE starting the engine is somewhere in the 12.0 to 12.7V range, and immediately goes up to 14.5 to 15.0 after engine start, as the alternator is charging as much as it can to replenish Starter draw.

It seems to be MORE than a coincidence that your blower motor quit working at (about) the same time as your lights quit flickering. I would get the Blower Harness recall performed. Actually I would inspect the wiring harness BEFORE getting the recall performed as that circuit is BATTERY POWER (UNswitched) as far as the power supply via F88 to the Blower Final Stage Connector. I would PULL F88, inspect it to see if it blew, and NOT reinstall it prior to blower harness recall perfomance. See wiring to N2, Blower Output Stage, in this TIS schematic:
https://www.newtis.info/tisv2/a/en/e...bution/ufClUrJ

My SWAG is that with that fuse pulled, you will have NO more flickering lights. For SURE, you will have no concern of electrical fire due to blower harness failure prior to recall -- IF you have pulled F88.

George

I pulled the 40 amp fuse (f88) I started the car and my lights flickered for 5 seconds then stopped. Headlights and brake lights are now not flickering at all. However my interior footwells lights still do when the doors are open but stop when closed. My reverse lights flicker when in reverse but not all the time like before. All of my turn signals use to randomly flash as well. That stopped. I can at least drive at night now. So that seemed to fix some of it. I didn't have time to look at the connections to the blower motor. I have called BMW about 8 times and the service guy won't answer.

[18lstroup]

Bad news. Just got in the car. All the lights are flickering again.

[gbalthrop]

Originally Posted by 18lstroup

Bad news. Just got in the car. All the lights are flickering again.

I would:
1) Activate Hidden Menu 9.00 or attach a scan tool to read System Voltage Parameter while motor runs;
2) Change engine RPM to as much as 3,000 RPM, "blipping" accelerator pedal, to see if alternator RPM has any relationship to flickering lights.
3) Also try changing the "Electrical Load" on the system by turning off the headlights, turning blower or seat/window/mirror heaters on/off, and generally experiment with load conditions that cause or eliminate flicker of interior lights such as dome/reading lights, etc.
4) If you have NOT already done so, check BOTH battery cables to make sure they are snug on the battery terminal posts, and also check the Negative cable connection to the chassis to make sure it is tight & corrosion-free.

Depending upon the "Refresh Rate" of a DMM or digital voltage readout, it may NOT pickup quick voltage changes reflected by flickering lights, and if you had an old analog meter to attach to the lighter socket or Jumpstart terminals, that might provide better diagnostics.

In other words, even if the cause of the flickering lights IS voltage fluctuation, selecting the best tool to correctly measure the fluctuations may be the difficult part of the diagnostics.

There IS an answer to this, it just will take some experimentation and creative testing to identify the cause.

Please keep at it & let us know,
George

[18lstroup]

I just got my car back last night from the recal. He said the blower motor connector was pretty melted. They replaced that and replaced the blower motor resistor. The good news is I have heat again. The bad news is my lights still flicker.

[gbalthrop]

Originally Posted by 18lstroup

I just got my car back last night from the recal. He said the blower motor connector was pretty melted. They replaced that and replaced the blower motor resistor. The good news is I have heat again. The bad news is my lights still flicker.

So now the possible causes of the flicker appear to be:
1) Erratic Alternator Voltage output (probably need Analog meter to test, as flicker may be too fast for digital); we're looking for a "dancing needle"
2) FRM internal fault
3) Loose/Damaged Power Supply wire or ground in the FRM voltage supply circuit or lighting circuit.

It usually makes sense to FIRST test the things you can inspect or test YOURSELF, without throwing parts at it, or paying $$$ for diagnostics you don't have equipment for.

So, going back to the title you gave this thread, "335xi ground connections" it is possible that the original focus was misdirected at individual bulb/ electrical consumer grounds as opposed to the FRM grounds. So looking at the FRM wiring diagram for your car, we see two possible grounds which if defective, COULD cause flickering in ALL lights, or at least in multiple lights on the same circuit, such as interior lamps, namely X173 & X10012 as identified in this circuit diagram and the two "Installation Locations":
https://www.newtis.info/tisv2/a/en/e...module/heWpfsY
https://www.newtis.info/tisv2/a/en/e...xi-cou/RJjERP6
https://www.newtis.info/tisv2/a/en/e...i-cou/FZ8VyJCH

For those NOT familiar with TIS circuit diagrams, the Chassis Grounds such as X173 are Brown wires. Just to do anything you can do yourself without diagnostic equipment, you might check that those two ground Connectors are clean, dry, no corrosion, and chassis attachment is snug. Test Continuity to ground with Multimeter (Ohms) as you jiggle the connector as well as inspect visually. Use Electronic Contact Cleaner or even WD-40 on any corrosion, or even emery paper or light filing on any obvious rust, to get clean metal-to-metal contact.

Ideally, if you have a Windows 10 laptop, I would invest $15 to $45 in a K+DCAN cable, download & install INPA (see BimmerGeeks.com for both), read (and save ScreenPrint as jpg file) ALL codes using "Functional Jobs" F4, F1, Read Fault Memory ALL Modules (Fehlerspeicher Lesen), and attach that jpg screenprint to a post here so someone can suggest next step. You will save a LOT of money if you can diagnose a fault of this type yourself without having to pay $100 or more just to have a shop read codes. There is a LOT more that INPA can do in addition to reading codes, but that is the place to start.

Don't be afraid to try INPA just because much of it is in German. You can learn how to use "Functional Jobs" in an hour or less (just post here if you hit a snag), and with help from the Forum, you can do other diagnostics as required, a step-at-a-time, and you will have the same diagnostic tools that shops charge you hundreds to use on your vehicle. There WILL be times when a good Tech's knowledge exceeds the mostly entry-level info you will get here, but initial diagnostics is NOT one of those times.

Please let us know what you find,
George