Footwell module error - headlights trigger door open sign when driving

[Vandie]

Hi guys

I own a 320d E90 2011
I have a strange issue. When I drive and switch my headlights on, my door sensors says that my doors are open. I've done a diagnostic test, and it pointed to my footwell module. I've since bought a second hand one (fairly new) and it's doing the same thing. Only when headlights are on and I'm driving. Without lights everything is fine.

Anyone else out there that had the same issue? And got it fixed ? Im running out of solutions.

 

[Nastaliq]

the footwell module is placed in a place where it can get wet from car shampooing, and the connectors can be corroded, but also water can get into the wiring.
what are you using for diagnostics?

1. A second hand module must be matched and coded to your car. you need ISTA for this. you might also need to re-fresh your cars i-level or i-step, older firmware can misinterpret signals.
2. Electrical load from headlights changes the system voltage and can expose weak grounds or alternator fluctuation in current supply. A weak ground is a very obvious thing if the footwell module is cooked. Ground connections get corroded and you get a shit ground connection. clean all grounds in the footwell properly and spray with electrical contact cleaner then torque down properly. I have seen grounds tightened so hard, that the wires crimped out and had weak contacts. The nut looked like Thor tightened it, but the wires were loose
3. Check for >0.3 V across the battery at idle with lights on; if higher, I suspect alternator diodes will need to be checked, less commonly happening, but still possible. 9 out of 10 times its weak contacts to ground.
4. Finally check the door latch microswitch/latch. Sometimes theres abrasion in that rubber hose and the wires are contacting or crimped completely. Use ISTA "status of contacts" or something similar. I cant remember, use live-readout.
5. Check fuses.

this should help you get to the bottom of it.

 

[modocrat]

Easiest fix: Don't switch on your headlights 😎

 

[Vandie]

the footwell module is placed in a place where it can get wet from car shampooing, and the connectors can be corroded, but also water can get into the wiring.
what are you using for diagnostics?

1. A second hand module must be matched and coded to your car. you need ISTA for this. you might also need to re-fresh your cars i-level or i-step, older firmware can misinterpret signals.
2. Electrical load from headlights changes the system voltage and can expose weak grounds or alternator fluctuation in current supply. A weak ground is a very obvious thing if the footwell module is cooked. Ground connections get corroded and you get a shit ground connection. clean all grounds in the footwell properly and spray with electrical contact cleaner then torque down properly. I have seen grounds tightened so hard, that the wires crimped out and had weak contacts. The nut looked like Thor tightened it, but the wires were loose
3. Check for >0.3 V across the battery at idle with lights on; if higher, I suspect alternator diodes will need to be checked, less commonly happening, but still possible. 9 out of 10 times its weak contacts to ground.
4. Finally check the door latch microswitch/latch. Sometimes theres abrasion in that rubber hose and the wires are contacting or crimped completely. Use ISTA "status of contacts" or something similar. I cant remember, use live-readout.
5. Check fuses.

this should help you get to the bottom of it.

Thanks man
the footwell module is placed in a place where it can get wet from car shampooing, and the connectors can be corroded, but also water can get into the wiring.
what are you using for diagnostics?

1. A second hand module must be matched and coded to your car. you need ISTA for this. you might also need to re-fresh your cars i-level or i-step, older firmware can misinterpret signals.
2. Electrical load from headlights changes the system voltage and can expose weak grounds or alternator fluctuation in current supply. A weak ground is a very obvious thing if the footwell module is cooked. Ground connections get corroded and you get a shit ground connection. clean all grounds in the footwell properly and spray with electrical contact cleaner then torque down properly. I have seen grounds tightened so hard, that the wires crimped out and had weak contacts. The nut looked like Thor tightened it, but the wires were loose
3. Check for >0.3 V across the battery at idle with lights on; if higher, I suspect alternator diodes will need to be checked, less commonly happening, but still possible. 9 out of 10 times its weak contacts to ground.
4. Finally check the door latch microswitch/latch. Sometimes theres abrasion in that rubber hose and the wires are contacting or crimped completely. Use ISTA "status of contacts" or something similar. I cant remember, use live-readout.
5. Check fuses.

this should help you get to the bottom of it.