SOLVED - Door open warning light on, (was not Door Latch Micro switch, was not Loom bellows, but it was the Window Motor/Door Module)

[logrover]

This one took me a while to trace, so I thought I'd document it to maybe help others.

 

Fault - (2009 Fabia 1.2 Hatchback, BBM) Door open light and chime and interior lights coming on at random whilst driving and stationary. Fault was intermittent so made it harder to test.

 

Summary - Opening and closing each of the doors wasn't conclusive but I thought it was drivers door when I could get the fault to occur. I read up on here and then checked the wiring in A pillar bellows (all looked good unusually), so I then removed the door latch mechanism as described in posts on here. I tested the latch micro switch on the bench and all seemed good. I checked the PCB contacts for the connector and switches both visually and with meter for continuity and all seemed good. I ran 9v from a battery through switch and all good. I then removed the complete door loom (a little fiddly but it can be done without removing the speaker) and double checked all wires - all good. Having not found any problem with door lock mechanism or door loom I decided to put it back together and reinstall without changing micro switches or re-soldering so as not to disturb anything.

 

I then looked at wiring diagrams in posts on here to see if something else could be happening. It showed that the door latch circuit has two wires (brown, brown/yellow) and when the door is open then these connect in the latch micro switch and earth is supplied to the brown/yellow cable and that feeds back through the bellows to the Convenience unit under the dash. However, there is another brown/yellow cable that goes from the same pin in the bellows connector to the Window Motor/Door Control (not sure why). This meant I could easily test the state of both brown/yellow wires at the window motor connector with the door in operation (have door open all the time and just use a screwdriver to push the door catch cam all the way in to simulate it being closed). Doing this when the connector was off the window motor I was able to see the door catch micro switch always operated perfectly and only completed the earth circuit when the door was open (and the dash light operated correctly). However, when I reconnected the connector to the window motor, that wire was earthed intermittently and caused the dash door open warn light to come on even when door was closed. So I concluded the window motor was incorrectly earthing out the circuit and causing the fault. 

 

As an aside, using this window motor connector (status of brown/yellow wire when unplugged) would be a good way to test the door micro-switch operation without needing to dismantle door catch as easier to get to than the bellows connector and allows window motor to be excluded from the test (as its unplugged).

 

So I then decided to strip the window motor as couldn't find much info on here. First time stripping it came apart completely and I found a very tiny spot of green corrosion, some metal filings, but not much else so I cleaned and sealed up the pins on the board with PCB varnish thinking it was maybe just moisture or filings causing a short. Reassembled, tested, just the same fault.... So took it off again (three screws, easy), and second stripping it came apart in better way and PCB easier to access. I tested what i could with a meter for continuity of soldered joints behind main connector, but everything else was tiny SMD stuff so beyond me. I didn't find a fault but decided to reflow the solder on the connector joints as they cause issues elsewhere (dash, lock pcb etc). They are small and fiddly, but I got it done and then added PCB varnish on top. Reassembled everything, and everything now works as it should - the original fault of door open light coming on has not happened since.

 

I did look at replacement window motors before i stripped it and there are many versions, and some are costly, so this might be an option to try before going that route.

 

The circuit board is small and I couldn't see detail that well (corrosion, joints, filings, etc) so I zoomed in on camera and took lots of photos, then zoomed in again whilst viewing and surprising what can be seen then!

 

Some pics below, but they are just a fraction of the couple of hundred I must have taken....

 

Testing the door latch on bench (now know this could have been avoided by testing in situ through the window motor connector)

 

 

Model of window motor on this 2009 1.2 hatchback

 

 

Window motor connector (brown/yellow at bottom right here is the wire that should be earthed when latch closed (test with connector unplugged from window motor to test latch micro switch first, then plugged in to see if Window motor is providing a false earth).

 

 

Connector block on Window Motor PCB, - small amounts of corrosion, but perhaps more under the block itself, but didn't fancy trying to remove.

 

 

PCB from Window Motor with my thumb for scale (board is small....) - I reflowed solder on back of connector block (the 14 blobs in the middle - they look a bit domed but connectivity was good and I was concerned at leaving too much heat on the pads with all those SMD's around...) PCB Varnish added on top to seal out any moisture.

 

 

Hope that helps someone. I have more pics of dismantling things is required (but there was a 10mb limit on this post).

 

 

[HTB]

Hello There,

Great post, I think my son’s car has a similar problem, door open light on dash as well as locking problems. I’d be very interested to see more pictures of the dismantling if possible?

 

 

[viejita]

I have this same problem - the doors open dashboard light keeps coming on, even when all doors are closed, accompanied by the occasional dinging sound. As the dashboard lights are on, it seems as though the interior overhead lights read that doors are open and stay on as well. I simply turned that off. Recently, I see that the electric window controller on the driver side will not function for the window on the passenger side but the passenger side window button still works. Today whilst driving, the passenger window started going up and down of its own accord which would not be ideal if it was raining. Reading through this post, do you think these issues are linked? I am not a mechanic so will have to take the car to the mechanic but if anybody on here has experienced this and knows the solution, it would be good so that I could let them know and save myself a few bob with them having to do lots of exploration. 

Thanks

[HTB]

Hi Viejita,

It definitely seems to be a problem with the driver’s side window motor as I have taken the fuse out for the windows and the doors lock normally and door open light has gone off. I have yet to change the motor but as everything else works now it seems to be pointing to this. I plan to change it in a couple of weeks and will let you know how things go. 

[viejita]

Thanks HTB. I will await your response.

 

Now all I need to do is work out why the boot won't open unless I open a rear door first!!!

 

Thanks

[sepulchrave]

4 hours ago, viejita said:

Thanks HTB. I will await your response.

 

Now all I need to do is work out why the boot won't open unless I open a rear door first!!!

 

Thanks

 

It's to prevent purse snatching at the traffic lights, you have to open a door with a functional microswitch first.

[viejita]

Hi Sepluchrave

 

As I am not a mechanic or understand cars, I do not understand your response. Are you talking about the boot or the door lock issue? Can you explain a bit more please? In layman's terms.

 

Thanks

[sepulchrave]

4 hours ago, viejita said:

Hi Sepluchrave

 

As I am not a mechanic or understand cars, I do not understand your response. Are you talking about the boot or the door lock issue? Can you explain a bit more please? In layman's terms.

 

Thanks

 

The door lock issue is causing the boot issue.

[viejita]

Hi HTB

 

Did you change the motor yet? I am keen to know whether it worked before I go to my mechanic armed with this forum thread!

 

Thanks

 

Jo

[Plimsol]

Hi viejita,

 

I have the exact same problem you have, i.e passenger window opening on its own intermittently, and door open light staying on.  Did you resolve your fault, or get confirmation that it is the driver side window motor?
 

Thanks 

[viejita]

Hi Plimsol

 

No, I haven't done anything yet as both the light and the window have been ok recently. If you decide to get yours looked at, please do let me know the solution.

 

Thanks

 

Jo

[HTB]

I changed the window motor and all problems ceased. Door locks, windows work normally and door open light goes off when the door shuts and interior light goes off. 

[viejita]

Woo hoo. Great news

[jackam]

Great post, I've been struggling with this... had all the door looms apart and no breaks, everything looks fine, problem persists. Will pull the fuses to the window motor and see what happens.

 

Interestingly enough previous owner had a mechanic do some work to the window motor...

[graz126]

Can anybody tell me if this part or the socket it plugs into have any micro switches in it, or are all connections wired straight through? Thanks in advance. 

[Breezy_Pete]

Nope, that's just a connector, as is the mating part in the A-pillar

[Breezy_Pete]

On 15/03/2021 at 20:03, logrover said:

Connector block on Window Motor PCB, - small amounts of corrosion, but perhaps more under the block itself, but didn't fancy trying to remove.

 

 

I've looked at a few of this version recently, and can confirm that under that connector seems to be where moisture is causing trouble, by corroding copper tracks and planes.

Awkward to remove. I cut a slice of thick copper sheet that just fitted between the rows of pins on the bottom of the board, then wetted that to all the pins with solder and heated up until the connector dropped out. Could no doubt do it with hot air too, but might be tricky to avoid collateral damage.

[Thud]

Hi all, sorry if I'm hi-jacking this thread, but it's kind of relevant, I think.

 

On 21/02/2024 at 14:37, Breezy_Pete said:

Nope, that's just a connector, as is the mating part in the A-pillar

 

I've been chasing an intermittent central locking fault, front passenger door and I reckon I've found it. T28  yeehah

My question is, does anyone know the size/name/part number of the female crimp terminals I'll need to replace the connections indicated in the pictures. Marked 4 (br/ge), the crimp connector has snapped in the housing, wire 6 (green/blue) looks to have snapped clean off at the crimp. It looks clean enough to have been cut, but who'd want to do that? The wire guage on both these wires is 0.35. There will probably be a few more dodgy connections I haven't found yet. I may need to replace a few more but kind of doubt as all the rest of the door electics are ok. Any hints or tips as to the best way to go about this repair welcomed.

 

Cheers