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Discussion Starter #1
Hello !

I'm having problem with battery drain and it was the footwell module that was causing the drain, it won't got to sleep and as a result its draining 1.5ah.

Other than the drain, not having any functional issue.

Question is, can it be fixed somehow ? resetting and such ? (checked for circuit fault but nada).

Else, can i replace it with FRM2 or 3 ? it must have specific compatibility ? or i can use any FRM for BMW E90 series ?

Kind Regards,

Ektor
 

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Kostspieliger Spaß Quandt
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If it is the FRM the only thing in the FRM module that really can drain a battery is the built in door relays. What other issues does the car have? Does it have difficulty with one or more doors - do the doors take a while to unlock after pressing the remote. Any crash history for the car? The footwell module (FRM) is only wakened via the following signals:
K-CAN active
Terminal 15 ON
Hazard-warning switch ON
Change in status of door contacts
Anti-theft alarm system triggered

If the FRM were draining a battery it would manifest in a symptom of one of the above events.
 

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Discussion Starter #3
Doesn't seems to have any of those problems.

But everything started when I changed the high beam bulbs.

When I remove the fuses regarding the headlights, drain stops.
 

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Kostspieliger Spaß Quandt
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This is a new one to me? What happens if you replace the new bulbs with the old?


The footwell module (FRM) is an electrical nodal point in the footwell on the drivers side. The footwell
module picks up the signals from the doors and controls the lighting. The footwell module also controls
the adaptive headlights. The footwell module is also the interface to the dashboard.

Note: System description for the adaptive headlight
There is a separate system description for the adaptive headlights.
[For further information, please refer to BMW Service Technology (SBT) 63 02 03 007]
Brief component description
The following components deliver signals for the footwell module:
A number of control units are involved in the lighting system. In a stricter sense, the following control
units are involved in the lighting (in alphabetical order):
- Height sensors
- Reversing light switch
- Brake light switch
- Hazard warning flasher switch
- Light switch
- Driver's door switch block
- Door contacts in rear doors
- Door

In accordance with the traffic situation, the high-beam assistant sends a switch-on
recommendation or a switch-off recommendation for the high-beam headlights to the footwell
module (FRM). On the basis of this recommendation and various other the input variables, the
footwell module decides whether the main-beam headlights should be switched on or off.
[for more information, please refer to SI Technology (SBT) 63 01 05 140]
 

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Discussion Starter #5
Already tried changing the bulbs back to the old.

No ahl..

But the drain stops only when I remove the fuses.

From ista, it diagnoses that it won't go to sleep
 

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Kostspieliger Spaß Quandt
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Already tried changing the bulbs back to the old.

No ahl..

But the drain stops only when I remove the fuses.

From ista, it diagnoses that it won't go to sleep
I would be more apt to think an input signal was keeping it awake as opposed to the module itself. If I understand you correct - you remove the headlight fuses and the module performs correctly? Sounds more like a light issue than the FRM
 

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Discussion Starter #7
You mean that one of bulbs or the wiring keeps it awake?

Any ideas how to trace it down and idea how to fix it?
 

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Discussion Starter #9

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Kostspieliger Spaß Quandt
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You know the battery is in good shape? Lot's of cranking amps? You need to test the battery amps not just voltage.

A 15 minute draw to no start condition for a fully charged good battery is a serious draw and would indicate a high amp short. I can leave all my lights on that long and have no issue. If disconnecting the light fuses prevents the drain then you're gonna have to dig out wiring diagrams and a multi-meter and check all the light wiring and harness connections - you might be in luck as I've noted more folk on this forum very keen and knowledgeable about the wiring diagrams of this chassis BMW than any other.
 

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Discussion Starter #11
Not in 15 minutes.. In hours!
But what may happened and started that problem after bulb change? Short circuit occurred?

You know the battery is in good shape? Lot's of cranking amps? You need to test the battery amps not just voltage.

A 15 minute draw to no start condition for a fully charged good battery is a serious draw and would indicate a high amp short. I can leave all my lights on that long and have no issue. If disconnecting the light fuses prevents the drain then you're gonna have to dig out wiring diagrams and a multi-meter and check all the light wiring and harness connections - you might be in luck as I've noted more folk on this forum very keen and knowledgeable about the wiring diagrams of this chassis BMW than any other.
 

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Discussion Starter #13
OK I checked the headlights with the meter.. All good. No drain of any kind.
How to check the doors?
Sorry I thought you said 15 mins. Try disconnecting each headlight housing harness one at a time while monitoring the draw. The internal wiring inside the housing is prone to fail - the plastic insulation flakes off. You might narrow it down to one unit.
 

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OK I checked the headlights with the meter.. All good. No drain of any kind.
How to check the doors?
But wait - you stated if you unplugged the headlight fuses the drain stopped? Is that the case?

I mentioned to disconnect the headlight harnesses one at a time so you might be able to narrow down a particular headlight assembly or harness.

The headlight wiring goes from each unit to the light control switch then to the FRM. - Check the light switch.

https://www.newtis.info/tisv2/a/en/...ing-light-high-beam-headlight-flasher/pis4xna
 

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Discussion Starter #15
But wait - you stated if you unplugged the headlight fuses the drain stopped? Is that the case?

I mentioned to disconnect the headlight harnesses one at a time so you might be able to narrow down a particular headlight assembly or harness.

The headlight wiring goes from each unit to the light control switch then to the FRM. - Check the light switch.

https://www.newtis.info/tisv2/a/en/...ing-light-high-beam-headlight-flasher/pis4xna
Yeah i unplugged the each headlight from the harness and no change from the drain.

My guess is since i remove the fuses the FRM is out of power. Should i check also the back lights ?

What other car features FRM controls ?
 

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I’m in the same situation with the overnight battery draw due to a bad FRM. However, my car also has a rear window warning on dash, no central locking or key FOB, front windows operate but rear windows do not from driver door switch, etc. If it were the FRM, there’s usually effects with multiple functions. FRM controls all lights, horn, DRL function but operation is thru the module above rear view mirror. The FRM must be recoded to your car and is easy to do IF you have the correct equipment (which I do not). Save yourself the headache and have it diagnosed at the dealership (or comp shop).


Sent from my iPad using Bimmerfest
 
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