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Discussion Starter #1
Sometimes when I park my car and forget to turn off my lights (with euroswitch), there's no warning sound. Also when I open the front doors the overhead ambiance lights doesn't come on. If I open the rear doors or the trunk, the ambiance lights come on. What could be the problem? Front door micro switch?

Even though I don't know if it's related, when I use my remote to lock the car, only sometime the small red alarm light (driver door knob) goes on.........Hate electrical issues..

Any help much appreciated..Thanks
 

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All signs would point to a failed door latch microswitch. It's a pretty common problem and there are ways to DIY the repair or there are some options for full replacement of latch/switch mechanism.

I have DIY'ed a couple but recently some of the AliExpress and BangGood sellers have had the entire assembly for under $20. For me that was low enough to take a chance on and the replacements in my wagon have been working fine for about 2.5 years now.

Sent from my Pixel 3a XL using Tapatalk
 

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It appears that you have a problem with the "door open switch circuit".
Cracked solder joints where the red wire and blue wire are soldered to the PCB.
If you get to the PCB, I suggest you re-solder all solder joints on it.

Door Lock Issues
First you should scan Address 46 CCM with VCDS. (or other VAG scanner)

Ensure the lamp is good before testing the rest.
If the puddle light ever comes on with the door closed, the "door open switch" is almost certainly not functioning correctly.
If the puddle light ever does not come on with the door open, the "door open switch" or its wiring (including solder joints on the PCB) is almost certainly faulty.

Front Door Lock (Rear doors are similar)
You should lower the window into the service position (2"-3" open) before you disconnect the battery.
No need to remove the window completely, just tape it up securely. (Put paper/plastic over top of door to protect paint)
Door Lock Mechanism Repair (With Pics) (Modified copy from www.taligentx.com)
Also check the wiring and connectors between the doors and pillars.

All Doors
Additional information on the "puddle light/door open switch".
Stupid door Switch!! $3 Fix!!!
 

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Discussion Starter #4
It appears that you have a problem with the "door open switch circuit".
Cracked solder joints where the red wire and blue wire are soldered to the PCB.
If you get to the PCB, I suggest you re-solder all solder joints on it.

Door Lock Issues
First you should scan Address 46 CCM with VCDS. (or other VAG scanner)

Ensure the lamp is good before testing the rest.
If the puddle light ever comes on with the door closed, the "door open switch" is almost certainly not functioning correctly. Most likely. I've seen it flashing just before the door shuts. And that could also explain my battery drainage..

If the puddle light ever does not come on with the door open, the "door open switch" or its wiring (including solder joints on the PCB) is almost certainly faulty. Same here. Sometimes on but mostly off....
Thx a million for your detailed answer......
Maybe easier to change the whole module...? If this is the correct part number 3B1837015Q? I can get it cheap (30 US) at a junkyard.
 

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I wouldn't put a used one in without first repairing the solder joints.
It would be better to just fix the original one.
 

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Discussion Starter #6
One more question..:
If I try to lock the doors from the driver's door panel, not all doors lock. The left front door stays open. The door knob goes down but then up again. Is this normal? I remember reading something about it...safety thing..? Or should I be able to look all four doors from inside?
 

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The locking issue is almost certainly related to the door lock module issues. There is logic that will do some odd things if all the switches aren't working correctly.
 

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As FrescoGreen01.5 said.

Is your car RHD ?
You may have faults in both doors, but check the switches and re-solder all joints on the PCB in the driver side door lock module first.
 

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Discussion Starter #9
Tomvw
LHD....I think I'll start with driver's door.You have many aftermarket ones now days..New ones starts at 40 US$..
 

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Many aftermarket modules don't work well or for long.
IMO the best way is to repair the original module.
The module repair is easy, the hard part is removing and re-fitting it.
 

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Discussion Starter #11
Can some explain what's the difference between this parts? 3B0837867 and 3B1837015. I know that both are front left (driver) door modules.....Can you tell by the part number if the module is for central locking or not?
 

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I don't know what the differences are, but they are almost certainly not compatible.
I again suggest you look into repairing the original, and avoid complications.
 

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x2 on what Tomvw said.

Per the US Etka, 3B1 837 015 AK is the US part number for the left front door lock module (the "AK" is part of the number). I suspect the European part number is different--as I understand, European (and maybe "rest of world" (ROW), too) cars have "dead locking", meaning that you can't open a locked door from inside or outside the car.
In the US, you must always be able to open the door from the inside, so the US lock modules are different and incompatible. I believe the "dead locking" lock modules have a fourth microswitch not present in the US modules. The photo below is my US driver door lock module--notice the unpopulated location for the extra switch.
101544
 

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ROW cars with deadlocks, have the extra switch and also some extra mechanical parts.
You can use the instructions in the link in post #3, carefully note the positions of the extra parts during disassembly.
 
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